Ethylene/pentene-1 copolymer and ethylene/pentene-1 copolymer composition

ABSTRACT

The present invention relates to a novel ethylene/pentene-1 copolymer whose molded film has a good balance between impact resistance and tear properties and high transparency, also is prominently reduced in a variation of the transparency even after subjected to a heat treatment, and further shows high blocking resistance, provided that the copolymer fulfills specific requisites. The invention also relates to a process for the preparation of the above-mentioned ethylene/pentene-1 copolymer and a formulation of the ethylene/pentene-1 copolymer composition using a stabilizer. According to the invention, there can be obtained an ethylene/pentene-1 copolymer composition which is excellent in heat stability in the molding stage, long-term heat stability and weatherability.

FIELD OF THE INVENTION

The present invention relates to an ethylene/pentene-1 copolymer and aprocess for the preparation of the same. More particularly, theinvention relates to a novel ethylene/pentene-1 copolymer whose moldedfilm has a good balance between impact resistance and tear properties.The invention also relates to a process for the preparation of theabove-described ethylene/pentene-1 copolymer.

Further, the present invention relates to an ethylene/pentene-1copolymer composition, more particularly, to an ethylene/pentene-1copolymer composition which is excellent in heat stability in themolding stage, long-term heat stability and weatherability.

BACKGROUND OF THE INVENTION

Linear low-density polyethylene (LLDPE), that is a copolymer of ethyleneand α-olefin, shows higher impact strength when molded into a film, ascompared with conventional low-density polyethylene (LDPE) obtained bythe high pressure process, so that the linear low-density polyethylenehas been broadly used as a film-forming material.

In order to prepare such ethylene/α-olefin copolymer, there have beenused butene-1 or α-olefin having 6 or more carbon atoms as α-olefincomonomer.

A film obtained from an ethylene/butene-1 copolymer (i.e., an example ofthe linear low-density polyethylenes) is excellent in tear propertiesbecause of its adequate tear strength, but is somewhat low in the impactstrength.

A film obtained from a copolymer of ethylene and α-olefin having 6 ormore carbon atoms (i.e., other example of the linear low-densitypolyethylene) is excellent in the impact strength, but has such aproblem that the film cannot be easily torn because of too high tearstrength. In other words, the film obtained from such copolymer is badin the tear properties.

Accordingly, eagerly desired are ethylene/α-olefin copolymers which canprovide films of high impact strength and excellent tear properties.

The present inventors have earnestly studied to solve theabove-mentioned problems accompanied by the ethylene/α-olefin copolymerfilms. As a result, they have found that if an ethylene/pentene-1copolymer having been obtained by copolymerizing ethylene and pentene-1and fulfilling specific requisites is molded into a film, the resultingfilm is excellent in impact strength and tear properties. Thus,ethylene/pentene-1 copolymers and processes for the preparation of thesame according to the invention have been accomplished.

The present inventors have also found that an ethylene/pentene-1copolymer composition obtained by adding a specific stabilizer to theabove-mentioned ethylene/pentene-1 copolymer is excellent in heatstability in the molding stage, long-term heat stability andweatherability, and that a molded product obtained from the copolymercomposition can keep high impact strength and good tear properties bothinherently belonging to the ethylene/pentene-1 copolymer. Thus,ethylene/pentene-1 copolymer compositions according to the inventionhave been accomplished.

OBJECT OF THE INVENTION

The present invention is to solve the above-mentioned problems existingin the prior arts, and it is an object of the invention is to provide anethylene/pentene-1 copolymer whose molded film has a good impactstrength and tear properties.

It is another object of the invention to provide a process for thepreparation of the above-mentioned ethylene/pentene-1 copolymer.

It is a further object of the invention to provide an ethylene/pentene-1copolymer composition having high heat stability in the molding stage,excellent long-term heat stability and high weatherability, which isvery suitable for forming a molded product capable of keeping highimpact strength and excellent tear properties both inherently belongingto the ethylene/pentene-1 copolymer.

SUMMARY OF THE INVENTION

The first ethylene/pentene-1 copolymer of the present invention obtainedby copolymerization of ethylene and pentene-1 is characterized bysatisfying the following requirements (A)-(E).

(A) A melt flow rate of the copolymer as measured according to ASTM D1238E is 0.01-100 g/10 min,

(B) a density of the copolymer as measured according to ASTM D 1505 is0.87-0.96 g/cm³,

(C) the copolymer contains constitution unit derived from pentene-1 is1-25% by weight, and

(D) in the case that said copolymer is subjected to cast molding toprepare a film having a thickness of 40 μm, a ratio (RS) of impactstrength of the film to tearing strength of the film in the take-offdirection of the film satisfies the following formula:

    RS≧-20 log MFR-1000d+968

wherein MFR represents a melt flow rate of said copolymer, and drepresents a density of said copolymer,

(E) in the case that said copolymer is melted at 200° C., then slowlycooled to 50° C. at a cooling rate of 0.31° C./min and crystallized toprepare a sheet sample having a thickness of 0.5 mm, a DSC melt-peakpattern of the sample obtained when the sample is heated from 10° to200° C. at a heating rate of 10° C./min using DSC has two melt peaks,and a ratio (Hh/Hl) of a height of the peak (Hh) on the highertemperature side to a height of the peak (Hl) on the lower temperatureside and the density of said copolymer satisfy the following formula:

    60d-52.0<Hh/Hl<80d-69.0

wherein Hh represents a peak height on the higher temperature side, Hlrepresents a peak height on the lower temperature side, and d representsa density of said copolymer.

The second ethylene/pentene-1 copolymer of the invention obtained byvapor phase copolymerization of ethylene and pentene-1 is characterizedby satisfying the following requirements (A)-(E).

(A) A melt flow rate of the copolymer as measured according to ASTM D1238E is 0.01-100 g/10 min,

(B) a density of the copolymer as measured according to ASTM D 1505 is0.88-0.95 g/cm³,

(C) the copolymer contains constitution unit derived from pentene-1 is2-25% by weight

(D) in the case that said copolymer is subjected to cast molding toprepare a film having a thickness of 40 μm, a ratio (RS) of impactstrength of the film to tearing strength of the film in the take-offdirection of the film satisfies the following formula:

    RS≧-20 log MFR-1000d+968

wherein MFR represents a melt flow rate of said copolymer, and drepresents a density of said copolymer; and

(E) in the case that said copolymer is melted at 200° C., then slowlycooled to 50° C. at a cooling rate of 0.31° C./min and crystallized toprepare a sheet sample having a thickness of 0.5 mm, a DSC melt-peakpattern of the sample obtained when the sample is heated from 10° to200° C. at a heating rate of 10° C./min using DSC has two melt peaks,and a ratio (Hh/Hl) of a height of the peak (Hh) on the highertemperature side to a height of the peak (Hl) on the lower temperatureside and the density of said copolymer satisfy the following formula:

    60d-52.0<Hh/Hl<80d-69.0

wherein Hh represents a peak height on the higher temperature side, Hlrepresents a peak height on the lower temperature side, and d representsa density of said copolymer.

The third ethylene/pentene-1 copolymer of the invention obtained bysuspension copolymerization of ethylene and pentene-1 is characterizedby satisfying the following requirements (A)-(E).

(A) A melt flow rate of the copolymer as measured according to ASTM D1238E is 0.01-100 g/10 min,

(B) a density of the copolymer as measured according to ASTM D 1505 is0.90-0.96 g/cm³,

(C) the copolymer contains constitution unit derived from pentene-1 is2-15% by weight

(D) in the case that said copolymer is subjected to cast molding toprepare a film having a thickness of 40 μm, a ratio (RS) of impactstrength of the film to tearing strength of the film in the take-offdirection of the film satisfies the following formula:

    RS≧-20 log MFR-1000d+968

wherein MFR represents a melt flow rate of said copolymer, and drepresents a density of said copolymer; and

(E) in the case that said copolymer is melted at 200° C., then slowlycooled to 50° C. at a cooling rate of 0.31° C./min and crystallized toprepare a sheet sample having a thickness of 0.5 mm, a DSC melt-peakpattern of the sample obtained when the sample is heated from 10° to200° C. at a heating rate of 10° C./min using DSC has two melt peaks,and a ratio (Hh/Hl) of a height of the peak (Hh) on the highertemperature side to a height of the peak (Hl) on the lower temperatureside and the density of said copolymer satisfy the following formula:

    60d-52.0<Hh/Hl<80d-69.0

wherein Hh represents a peak height on the higher temperature side, Hlrepresents a peak height on the lower temperature side, and d representsa density of said copolymer.

The first process for the preparation of an ethylene/pentene-1 copolymercomprises copolymerizing ethylene and pentene-1 in the presence of acatalyst containing solid catalyst components, wherein theethylene/pentene-1 copolymer obtained satisfies the followingrequirements (B)-(D).

(B) a density of the copolymer as measured according to ASTM D 1505 is0.87-0.96 g/cm³,

(C) the copolymer contains constitution unit derived from pentene-1 is1-25% by weight

(D) in the case that said copolymer is subjected to cast molding toprepare a film having a thickness of 40 μm, a ratio (RS) of impactstrength of the film to tearing strength of the film in the take-offdirection of the film satisfies the following formula:

    RS≧-20 log MFR-1000d+968

wherein MFR represents a melt flow rate of said copolymer, and drepresents a density of said copolymer.

In accordance with the first process for the preparation of anethylene/pentene-1 copolymer, there may be obtained theethylene/pentene-1 copolymer satisfying the specific requirements asmentioned above in high yield, and a film molded out of this copolymeris found to be excellent in balance between impact resistance andtearability.

The second process for the preparation of ethylene/pentene-1 copolymeraccording to the invention comprises copolymerizing ethylene andpentene-1 by vapor phase copolymerization in the presence of a catalystcontaining solid catalyst component, wherein the ethylene/pentene-1copolymer obtained satisfies the following requirements (B)-(D).

(B) a density of the copolymer as measured according to ASTM D 1505 is0.88-0.95 g/cm³,

(C) the copolymer contains constitution unit derived from pentene-1 is2-25% by weight

(D) in the case that said copolymer is subjected to cast molding toprepare a film having a thickness of 40 μm, a ratio (RS) of impactstrength of the film to tearing strength of the film in the take-offdirection of the film satisfies the following formula:

    RS≧-20 log MFR-1000d+968

wherein MFR represents a melt flow rate of said copolymer, and drepresents a density of said copolymer.

In accordance with the second process for the preparation of anethylene/pentene-1 copolymer, there may be obtained theethylene/pentene-1 copolymer satisfying the specific requirements asmentioned above in high yield, and a film molded out of this copolymeris found to be excellent in balance between impact resistance andtearability.

The third process for the preparation of an ethylene/pentene-1 copolymeraccording to the invention comprises copolymerizing ethylene andpentene-1 in a suspension state in the presence of a catalyst containingsolid catalyst component, wherein the polymerization is carried out at astate where more than 30% by weight of the resulting copolymer is noteluted and a polymerization temperature of 0°-120° C. to prepare, andthe copolymer obtained satisfies the following requirements (B)-(D).

(B) a density of the copolymer as measured according to ASTM D 1505 is0.90-0.96 g/cm³,

(C) the copolymer contains constitution unit derived from pentene-1 is2-15% by weight

(D) in the case that said copolymer is subjected to cast molding toprepare a film having a thickness of 40 μm, a ratio (RS) of impactstrength of the film to tearing strength of the film in the take-offdirection of the film satisfies the following formula:

    RS≧-20 log MFR-1000d+968

wherein MFR represents a melt flow rate of said copolymer, and drepresents a density of said copolymer.

In accordance with the third process of the preparation of anethylene/pentene-1 copolymer, there may be obtained theethylene/pentene-1 copolymer satisfying the specific requirements asmentioned above, because the copolymer is carried out under specificconditions, and a film molded out of this copolymer is found to beexcellent in balance between impact resistance and tearability.

The ethylene/pentene-1 copolymer compositions of the invention arecharacterized by comprising (I) an ethylene/pentene-1 copolymer obtainedby copolymerization of ethylene and pentene-1, said copolymer satisfyingthe following requirements (A)-(E).

(A) A melt flow rate of the copolymer as measured according to ASTM D1238E is 0.01-100 g/10 min,

(B) a density of the copolymer as measured according to ASTM D 1505 is0.87-0.96 g/cm³,

(C) the copolymer contains constitution unit derived from pentene-1 is1-25% by weight

(D) in the case that said copolymer is subjected to cast molding toprepare a film having a thickness of 40 μm, a ratio (RS) of impactstrength of the film to tearing strength of the film in the take-offdirection of the film satisfies the following formula:

    RS≧-20 log MFR-1000d+968

wherein MFR represents a melt flow rate of said copolymer, and drepresents a density of said copolymer; and

(E) in the case that said copolymer is melted at 200° C., then slowlycooled to 50° C. at a cooling rate of 0.31° C./min and crystallized toprepare a sheet sample having a thickness of 0.5 mm, a DSC melt-peakpattern of the sample obtained when the sample is heated from 10° to200° C. at a heating rate of 10° C./min using DSC has two melt peaks,and a ratio (Hh/Hl) of a height of the peak (Hh) on the highertemperature side to a height of the peak (Hl) on the lower temperatureside and the density of said copolymer satisfy the following formula:

    60d-52.0<Hh/Hl<80d-69.0

wherein Hh represents a peak height on the higher temperature side, Hlrepresents a peak height on the lower temperature side, and d representsa density of said copolymer, and

(II) at least one compound selected from the group consisting of thefollowing (a)-(e).

(a) Phenolic stabilizer,

(b) organic phosphite stabilizer,

(c) thioether stabilizer,

(d) hindered amine stabilizer, and

(e) metal salt of higher aliphatic acid.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a DSC melt-peak pattern obtained by measuring "ultra-slowlycooled sample" of an ethylene/pentene-1 copolymer of the invention underconventional measuring conditions.

FIG. 2 is a DSC melt-peak pattern obtained by measuring conventionallycooled sample of an ethylene/pentene-1 copolymer of the invention underconventional measuring conditions.

FIG. 3 is a rough sectional view of the polymerization vessel used inthe embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is illustrated below in more detail.

The first ethylene/pentene-1 copolymers of the present invention arerandom copolymers which can be obtained by copolymerizing ethylene andpentene-1 under specific conditions. In the preparation of theethylene/pentene-1 copolymers of the present invention, small amounts ofother α-olefins or polyenes in addition to ethylene and pentene-1 may becopolymerized. Examples of such α-olefins include propylene,2-methylpropylene, 1-butene, 1-hexene, 4-methyl-1-pentene,3-methyl-1-pentene, 1-octene, 1-nonene, 1-decene, 1-undecene and1-dodecene. Examples of the polyenes include butadiene, isoprene,1,4-hexadiene, dicyclopentadiene and 5-ethylidene-2-norbornene.

The first ethylene/pentene-1 copolymers of the present invention have amelt flow rate (MFR) of 0.01 to 100 g/10 min, preferably 0.05 to 50 g/10min as measured according to ASTM D 1238E. When MFR is lower than 0.01g/10 min, the moldability of the resulting copolymers is lowered and thetransparency of films obtained from the copolymers is liable to belowered, while when MFR is higher than 100 g/10 min, mechanical strengthis apt to be lowered.

The first ethylene/pentene-1 copolymers of the present invention have adensity of 0.87 to 0.96 g/cm³, preferably 0.88 to 0.94 g/cm³ as measuredaccording to ASTM D 1505.

The first ethylene/pentene-1 copolymers of the present inventioncomprise 1 to 25% by weight, preferably 4 to 23% by weight, particularlypreferably 6 to 20% by weight of a constitution unit derived frompentene-1 and 75 to 99% by weight, preferably 77 to 96% by weight,particularly preferably 80 to 94% by weight of a constitution unitderived from ethylene.

The ethylene/pentene-1 copolymers may contain not more than 10% byweight, preferably not more than 5% by weight, particularly preferablynot more than 3% by weight of a constitution unit derived from one ormore α-olefins or polyenes in addition to ethylene and pentene-1 asmentioned above.

The ethylene/pentene-1 copolymer of the present invention was molten byelevating the temperature to 200° C. and crystallized by cooling it at acooling rate of 10° C./min to obtain a sheet of 0.5 mm in thickness as asample. The DSC melt-peak pattern of the sheet obtained by elevating thetemperature from 10° C. to 200° C. at a heating rate of 10° C./min byusing DSC shows three peaks (FIG. 2). On the other hand, theethylene/pentene-1 copolymer of the present invention was molten byelevating the temperature to 200° C. and then crystallized byultra-slowly cooling it at a cooling rate of 0.31° C./min to 50° C. toobtain a sheet of 0.5 mm in thickness as a sample (the thus-obtainedsample is hereinafter referred as ultra-slowly cooled sample). The DSCmelt-peak pattern of the sheet obtained by elevating the temperaturefrom 10° C. to 200° C. at a heating rate of 10° C./min by using DSC hastwo melt-peaks wherein the relationship between the ratio of Hh/Hl(wherein Hh is a peak height on the higher temperature side and Hl is apeak height on the lower temperature side) and the density (d) of thecopolymer fulfills the following formula [1] (FIG. 1).

    60d-52.0<Hh/Hl<80d-69.0                                    [1]

Preferably,

    60d-52.0<Hh/Hl<80d-69.1                                    [1']

Particularly preferably,

    60d-51.9<Hh/Hl<80d-69.2                                    [1"]

wherein Hh represents a peak height on the higher temperature side, Hlrepresents a peak height on the lower temperature side, and d is thedensity of the copolymer.

The analysis of the DSC melt-peak pattern of the ultraslowly cooledsample is made in the following manner. A tangent line is drawn on thefoot of the higher temperature side of the melt-peak on the highertemperature side by starting from a point on the melt curve at 30° C.The tangent line is referred to as a base line. A perpendicular line isdrawn from the highest point of the peak toward the base line, and thedistance between the intersecting point and the highest point of thepeak is referred to as the peak height.

The ratio (RS) of the impact strength of a film of 40 μm in thickness tothe tear strength thereof in the take-off direction is represented bythe following formula [2], said film being obtained by casting the firstethylene/pentene-1 copolymer having the above-mentioned characteristicsaccording to the present invention.

    RS≧-20 log MFR-1000d+968                            [2]

wherein MFR is the melt flow rate of the copolymer and d is the densityof the copolymer.

Preferably,

    RS≧-20 log MFR-1000d+973                            [2']

Particularly preferably,

    200≧RS≧-20 log MFR-1000d+975                 [2"]

When the ratio (RS) of the impact strength to the tear strength is lowerthan (-20 log MFR-1000d+968), the resulting film has poor tearproperties, though it has a high impact strength, or the resulting filmis inferior in impact strength, though it has good tear properties. Thefilm of 40 μm in thickness, used for the measurement of the RS value, isa film prepared by molding the ethylene-pentene-1 copolymer under thefollowing conditions into a film by using a T-die film molding machineequipped with a 65 mmΦ extruder.

Molding conditions:

Resin temperature: 220° to 240° C.

Chill roll temperature: 30° to 40° C.

Film-forming rate: 20 to 40 m/min

Draft ratio (film thickness/lip opening): 0.05 to 0.07

The cast film of 40 μm in thickness, obtained by processing thecopolymer of the present invention in the manner mentioned above has animpact strength of generally not lower than 1000 kg·cm/cm, preferablynot lower than 1200 kg·cm/cm.

It is preferred that the tear strength (T_(MD)) of said film in thetake-off direction and the melt flow rate (MFR) of theethylene/pentene-1 copolymer fulfills the relationship represented bythe following formula [3].

    Log T.sub.MD ≧-0.37 log MFR-5.1d+6.72               [3]

wherein d is the density of the copolymer.

Preferably,

    Log T.sub.MD ≧-0.37 log MFR-5.1d+6.65               [3']

Particularly preferably,

    Log T.sub.MD ≧-0.37 log MFR-5.1d+6.59               [3"]

Films excellent in impact strength as well as tear properties can beobtained from the ethylene/pentene-1 copolymers which fulfills therelationship represented by the above formula [3] with respect to thetear strength (T_(MD)) of the film in the take-off direction and MFR.

Pressed sheets of 2 mm in thickness obtained by molding theethylene/pentene-1 copolymers of the present invention as mentionedabove according to ASTM D 1928 have stress cracking resistance [SCresistance (ESCR), measured according to ASTM D 1692, antalocks 100%,50° C.] of at least 10 hr and satisfy the relationship represented bythe following formula [4-a].

    ESCR≧0.7×10.sup.4 (log 80-log MFR).sup.3 (0.952-d)[4-a]

wherein 2.0≦MFR≦50 and d is the density of the copolymer.

Preferably,

    ESCR≧0.9×10.sup.4 (log 80-log MFR).sup.3 (0.952-d)[4'-a]

Particularly,

    ESCR≧1.1×10.sup.4 (log 80-log MFR).sup.3 (0.952-d)[4"-a]

Further, pressed sheets of 2 mm in thickness, obtained by molding theethylene/pentene-1 copolymers of the present invention according to ASTMD 1928 have stress cracking resistance [SC resistance (ESCR), measuredaccording to ASTM D 1692, antalocks 10%, 50° C.] of at least 20 hr andsatisfy the relationship represented by the following formula [4-b].

    ESCR≧1.4×10.sup.4 (log 40-log MFR).sup.2 (0.952-d)[4-b]

wherein 1.0≦MFR≦20 and d is the density of the copolymer.

Preferably,

    ESCR≧1.7×10.sup.4 (log 40-log MFR).sup.2 (0.952-d)[4'-b]

Particularly preferably,

    ESCR≧2.0×10.sup.4 (log 40-log MFR).sup.2 (0.952-d)[4"-a]

Furthermore, pressed sheets of 2 mm in thickness, obtained by moldingthe ethylene/pentene-1 copolymers of the present invention according toASTM D 1928 have stress cracking resistance [SC resistance (ESCR),measured according to ASTM D 1692, antalocks 10%, 60° C.] of at least 50hr and satisfy the relationship represented by the following formula[4-c].

    ESCR≧0.50×10.sup.4 (log 100-log MFR)(0.952-d) [4-c]

wherein 0.1≦MFR≦5 and d is the density of the copolymer.

Preferably,

    ESCR≧0.65×10.sup.4 (log 100-log MFR)(0.952-d) [4'-c]

Particularly preferably,

    ESCR≧0.80×10.sup.4 (log 100-log MFR)(0.952-d) [4"-c]

Moreover, it is preferred that the haze of the above-mentioned pressedsheets and the melt flow rate (MFR) of the ethylene/pentene-1 copolymerssatisfy the relationship represented by the following formula [5].

    Log HAZE≦15d-0.45 log MFR-12.23                     [5]

wherein d is the density of the copolymer.

More preferably,

    Log HAZE≦15d-0.45 log MFR-12.26                     [5']

Particularly preferably,

    Log HAZE≦15d-0.45 log MFR-12.30                     [5"]

The press sheets of 2 mm in thickness, used for the measurements of theabove-mentioned physical properties were prepared from theethylene/pentene-1 copolymers according to ASTM D 1928.

The measurement of HAZE was made according to ASTM D 1003.

The ethylene/pentene-1 copolymer whose pressed sheet satisfies the abovementioned relations between stress cracking resistance and haze arecapable for giving molded articles, by injection molding, rotationmolding or inflation molding which are transparent and hardly arise aenvironmental stress craking, that is hardly arise the trouble ofcontent leakage.

The first ethylene/pentene-1 copolymer of the present inventionmentioned above may be prepared by the first process for the preparationof an ethylene/pentene-1 copolymer of the invention as will be mentionedhereinafter.

In the first process for the preparation of an ethylene/pentene-1copolymer of the invention, ethylene and pentene-1 are copolymerized,for example, in the presence of such olefin polymerization catalysts asmentioned below.

The olefin polymerization catalysts used in the first process for thepreparation of an ethylene/pentene-1 copolymer of the invention are, forexample, those disclosed by the present applicant in Japanese PatentL-O-P Publn. No. 811/1981. That is, the disclosed olefin polymerizationcatalysts contain

[A] a solid titanium catalyst component containing magnesium, titanium,halogen and an electron donor as its essential ingredients obtained bybringing (i) a liquid magnesium compound having no reducing ability and(ii) a liquid titanium compound into contact, as they are, with eachother in the presence of (iii) an electron donor having no activehydrogen, or by bringing said (i) and said (ii) into contact, as theyare, with each other, followed by contact with said (iii), and

[B] an organic compound catalyst component of a metal belonging to theGroups I to III of the periodic table.

The magnesium compounds having no reducing ability referred to herein,that is, magnesium compounds having no magnesium-carbon bond or nomagnesium-hydrogen bond, which are used in the preparation of the solidtitanium catalyst component [A] as mentioned above, may be those derivedfrom magnesium compounds having reducing ability. Concrete examples ofsuch magnesium compounds having no reducing ability as mentioned aboveinclude halogenated magnesium such as magnesium chloride, magnesiumbromide, magnesium iodide or magnesium fluoride;

alkoxymagnesium halide such as methoxy magnesium chloride, ethoxymagnesium chloride, isopropoxy magnesium chloride, butoxy magnesiumchloride or octoxy magnesium chloride;

aryloxy magnesium halide such as phenoxy magnesium chloride ormethylphenoxy magnesium chloride;

alkoxy magnesium such as ethoxy magnesium, isopropoxy magnesium, butoxymagnesium, n-octoxy magnesium or 2-ethylhexoxy magnesium;

aryloxy magnesium such as phenoxy magnesium or dimethylphenoxymagnesium; and

magnesoum carboxylate such as magnesium laurate or magnesium stearate.

The magnesium compounds having no reducing ability exemplified above maybe those derived from magnesium compounds having reducing ability orthose derived at the time of preparation of catalyst component. Themagnesium compounds having no reducing ability may be derived from themagnesium compounds having reducing ability, for example, by bringingsaid magnesium compounds having reducing ability into contact withpolysiloxane compounds, halogen containing silane compounds, halogencontaining aluminum compounds or compounds such as esters, alcohols,etc.

The magnesium compounds having reducing ability as referred to hereinmay include, for example, those having a magnesium-carbon bond ormagnesium-hydrogen bond. Concrete examples of such magnesium compoundsas having reducing ability include dimethylmagnesium, diethylmagnesium,dipropylmagnesium, dibutylmagnesium, diamylmagnesium, dihexylmagnesium,didecylmagnesium, ethylmagnesium chloride, propylmagnesium chloride,butylmagnesium chloride, hexylmagnesium chloride, amylmagnesiumchloride, butyl ethoxy magnesium, ethyl butyl magnesium, octyl butylmagnesium, butylmagnesium halide, etc.

Besides the above-exemplified magnesium compounds having reducingability or having no reducing ability, the magnesium compounds used inthe present invention may also be complex or composite compounds of theabove-exemplified magnesium compounds with other metals, or mixturesthereof. Further, the magnesium compounds used herein may also bemixtures of two or more of these compounds as mentioned above.

Of these magnesium compounds exemplified above, preferred are thosehaving no reducing ability, particularly halogen containing magnesiumcompounds. Of the halogen containing magnesium compounds, preferred aremagnesium chloride, alkoxy magnesium chloride and aryloxy magnesiumchloride.

The liquid magnesium compound (i) used in the preparation of the solidtitanium catalyst component [A] is suitably a solution of the magnesiumcompound having no reducing ability in a hydrocarbon solvent, electrondonor or a mixture thereof in which said magnesium compound is soluble.The hydrocarbon solvent used for preparing the liquid magnesium compoundmentioned above includes aliphatic hydrocarbons such as pentane, hexane,heptane, octane, decane, dodecane, tetradecane, kerosine, etc.;

alicyclic hydrocarbons such as cyclopentane, methylcyclopentane,cyclohexane, cyclooctane, cyclohexene, etc.;

aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene,cumene, cymene, etc.; and

halogenated hydrocarbons such as dichloroethane, dichloropropane,trichloroethylene, carbon tetrachloride, chlorobenzene, etc.

The solution of the magnesium compound in the hydrocarbon solvent asmentioned above may be obtained by various methods, though they varyaccording to the kind of the magnesium compound and of the solvent used,for example, a method in which the magnesium compound is mixed simplywith the solvent, a method in which a mixture of the magnesium compoundand the solvent is heated, and a method in which the magnesium compoundis added to an electron donor in which said magnesium compound issoluble, for example, alcohol, aldehyde, amine or carboxylic acid, anymixture thereof, or said mixture with other electron donor, followed byheating if necessary. For example, when a halogen containing magnesiumcompound is dissolved in a hydrocarbon solvent, alcohol is used in anamount of more than 1 mole, preferably from about 1 to about 20 molesand especially from about 1.5 to about 12 moles per mole of the halogencontaining magnesium compound used, though the amount of alcohol usedvaries according to the kind and amount of the hydrocarbon solvent usedand to the kind of the magnesium compound used. When aliphatichydrocarbons and/or alicyclic hydrocarbons are used as the hydrocarbonsolvents, alcohol is used in the proportion as defined above. In thatcase, it is particularly preferable to use alcohol of 6 or more carbonatoms in an amount of more than about 1 mole, preferably more than about1.5 moles per mole of the halogen containing magnesium compound used,because the halogen containing magnesium compound can be solubilized bythe use of a relatively small amount of the alcohol, and the resultingcatalyst component is found to be high in catalytic activity. In thatcase, when alcohol of not more than 5 carbon atoms is used alone, it isnecessary to use more than about 15 moles of the alcohol per mole of thehalogen containing magnesium compound used, and the catalytic activityof the resulting catalyst component is inferior to that attained in thesystem mentioned above. On the one hand, when aromatic hydrocarbons areused as the hydrocarbon solvents, it is possible to solubilize thehalogen containing magnesium compound by the use of alcohol in theamount as defined above, irrespective of the kind of alcohol used.

Contact between the halogen containing magnesium compound and alcohol ispreferably effected in the hydrocarbon solvent at a temperature ofusually above room temperature and, according to the kind of thehydrocarbon solvent used, at a temperature of higher than about 65° C.,preferably about 80° to about 300° C. and especially about 100° to about200° C. for a period of from 15 minutes to 5 hours, preferably from 30minutes to 2 hours. Preferred alcohols having not less than 6 carbonatoms include, for example, aliphatic alcohols such as 2-methylpentanol,2-ethylbutanol, n-heptanol, n-octanol, 2-ethylhexanol, decanol,dodecanol, tetradecyl alcohol, undecenol, oleyl alcohol and stearylalcohol;

aromatic alcohols such as benzyl alcohol, methylbenzyl alcohol,isopropylbenzyl alcohol, α-methylbenzyl alcohol and α,α-dimethylbenzylalcohol;

and aliphatic alcohols containing alkoxy group such as n-butylcellosolve or 1-butoxy-2-propanol.

Examples of other alcohols include those having not more than 5 carbonatoms such as methanol, ethanol, propanol, butanol, ethylene glycol andmethylcarbitol.

When carboxylic acid is used, preferred are organic carboxylic acidhaving not less than 7 carbon atoms, for example, capric acid,2-ethylhexanoic acid, undecylenic acid, nonylic acid and octanic acid.

When aldehyde is used, preferred are those having not less than 7 carbonatoms, for example, capric aldehyde, 2-ethylhexyl aldehyde and undecylicaldehyde.

When amine is used, preferred are those having not less than 6 carbonatoms, for example, heptylamine, octylamine, nonylamine, decylamine,laurylamine, undecylamine and 2-ethylhexylamine. When the carboxylicacids, aldehydes or amines exemplified above are used, a preferredamount thereof and a preferred temperature used therefor are practicallythe same as those employed in the case of the alcohols.

Examples of other electron donors which can be used in combination withthe above-mentioned magnesium compound-solubilizing donors are organicacid esters, organic acid halides, organic acid anhydrides, ethers,ketones, tertiary amines, phosphorous acid esters, phosphoric acidesters, phosphoric acid amides, carboxylic acid amides, nitriles, etc.Concrete examples of these electron donors are those similar to theelectron donors (iii) having no active hydrogen as will be mentionedlater.

The above-mentioned solution of the magnesium compound in hydrocarboncan also be formed by dissolving in the hydrocarbon other magnesiumcompound or magnesium metal convertible into the above-mentionedmagnesium compound while converting said other magnesium compound ormetal into the above-mentioned magnesium compound. For example, thesolution of a halogen containing magnesium compound having no reducingability in hydorcarbon can be formed by dissolving or suspending amagnesium compound having such a group as alkyl, alkoxy, aryloxy, acyl,amino or hydroxy, magnesium oxide or magnesium metal in a hydrocarbonsolvent having dissolved therein the above-mentioned alcohol, amine,aldehyde or carboxylic acid while halogenating said magnesium compound,magnesium oxide or magnesium metal with a halogenation agent such ashydrogen halide, silicone halide or halogen. Furthermore, a magnesiumcompound having no reducing ability can be solubilized in a hydrocarbonsolvent by treatment with a compound capable of extinction of reducingability, such as alcohol, ketone, ester, ether, acid halide, silanol orsiloxane, of Grinard reagent, dialkylmagnesium, magnesium hydride or acomplex compound thereof with other organometallic compound, forexample, such magnesium compound having reducing ability as representedby the formula

    M.sub.a Mg.sub.b R.sup.1.sub.p R.sup.2.sub.q X.sub.r Y.sub.s

wherein M represents aluminum, zinc, boron or beryllium atom, R¹ and R²each represent hydrocarbon radical, X and Y each represent the groupOR³, OSiR⁴ R⁵ R⁶, NR⁷ R⁸ or SR⁹ in which R³, R⁴, R⁵, R⁶, R⁷ and R⁸ eachrepresent hydrogen or hydrocarbon radical and R⁹ represents hydrocarbonradical, a, b>0, p, q, r, s≧0, b/a≧0.5, and when the number of valencesof M is taken as m, the equation p+q+r+s=ma+2b is satisfied and therelation 0≦(r+s)/(a+b)<1.0 is established.

In preparing the aforementioned catalyst, it is essential to use themagnesium compound having no reducing ability, but this does not meanthat a combination use of the magnesium compound having reducing abilityshould totally be excluded in that case. In many cases, however, thecombination use of the magnesium compound having reducing ability inlarge amounts is found to be unfavorable.

It is also possible to use a solution of electron donors as a solventfor the magnesium compound. Preferred examples of such electron donorsas used for this purpose are alcohol, amine, aldehyde and carboxylicacids as exemplified previously, and alcohol is preferred in particular.Examples of other electron donors are phenol, ketone, ester, ether,amide, acid anhydride, acid halide, nitrile, isocyanate, etc. Themagnesium compound may be dissolved in such an electron donor solutionas mentioned above under the conditions corresponding generally to thoseemployed in the case of dissolving the magnesium compound in thehydrocarbon solvent using the electron donor as mentioned previously.Generally, however, in this case the system must be maintained at hightemperatures and, therefore, from the viewpoint of preparing catalysts,the use of the solution of the magnesium compound in hydrocarbon isbetter than that of the solution of the magnesium compound in electrondonor to obtain the catalysts of high performance with case.

The titanium compound (ii) used in the preparation of the solid titaniumcatalyst component [A] includes, for example, tetravalent titaniumcompounds represented by the formula Ti (OR)_(g) X_(4-g) (wherein R is ahydrocarbon radical, X is halogen, and 0≦g≦4). More particularly, thesetitanium compounds include titanium tetrahalides such as TiCl₄, TiBr₄and TiI₄ ; alkoxytitanium trihalides such as Ti (OCH₃) Cl₃, Ti (OC₂H₅)Cl₃, Ti (O n-C₄ H₉)Cl₃, Ti (OC₂ H₅) Br₃ and Ti (O iso-C₄ H₉) Br₃ ;dialkoxydihalides such as Ti (OCH₃)₂ Cl₂, Ti (OCH₂ H₅)₂ Cl, Ti (O n-C₄H₉)₂ Cl and Ti (OC₂ H₅)₂ Br₂ ; trialkoxytitanium monohalides such as Ti(OCH₃)₃ Cl, Ti (OC₂ H₅)₃ Cl, Ti (O n-C₄ H₉)₃ Cl and Ti (OC₂ H₅)₃ Br; andtetraalkoxytitanium such as Ti (OCH₃)₄, Ti (OC₂ H₅)₄, Ti (O n-C₄ H₉)₄,Ti (O iso-C₄ H₉)₄ and Ti (O 2-ethylhexyl)₄.

Of these titanium compounds exemplified above, preferred are halogencontaining titanium compounds, in particular, titanium tetrahalides andespecially titanium tetrachloride. These titanium compounds may be usedeither singly or in admixture of two or more, and also they may bediluted, before use, with hydrocarbon compounds or halogenatedhydrocarbon compounds.

The electron donor (iii) having no active hydrogen used in thepreparation of the solid titanium catalyst component [A] includesorganic acid esters, organic acid halides, organic acid anhydrides,ethers, ketones, tertiary amines, phosphorous acid esters, phosphoricacid esters, phosphoric acid amides, carboxylic acid amides, nitriles,etc. Concrete examples of such electron donors as mentioned aboveinclude:

ketones of 3-15 carbon atoms such as acetone, methyl ethyl ketone,methyl isobutyl ketone, acetophenone, benzophenone and benzoquinone;

aldehydes of 2-15 carbon atoms such as acetaldehyde, propionaldehyde,octylaldehyde, benzaldehyde, toluylaldehyde and naphthoaldehyde;

organic acid esters of 2-30 carbon atoms such as methyl formate, methylacetate, ethyl acetate, vinyl acetate, propyl acetate, octyl acetate,cyclohexyl acetate, ethyl propionate, methyl butyrate, ethyl valerate,methyl chloroacetate, ethyl dichloroacetate, methyl methacrylate, ethylcrotonate, ethyl cyclohexanecarboxylate, methyl benzoate, ethylbenzoate, propyl benzoate, butyl benzoate, octyl benzoate, cyclohexylbenzoate, phenyl benzoate, benzyl benzoate, methyl toluylate, ethyltoluylate, amyl toluylate, ethyl ethylbenzoate, methyl anisate, n-butylmaleate, diisobutyl methylmalonate, di-n-hexyldicyclohexenedicarboxylate, diethyl nadate, diisopropyltetrahydrophthalate, di-n-butyl phthalate, di-2-ethylhexyl phthalate,γ-butyrolactone, δ-valerolactone, coumarin phthalide and ethylenecarbonate;

acid halides of 2-15 carbon atoms such as acetyl chloride, benzoylchloride, toluylic acid chloride and anisic acid chloride;

ethers and diethers each having 2-20 carbon atoms such as methyl ether,ethyl ether, isopropyl ether, butyl ether, amyl ether, tetrahydrofuran,anisole and diphenyl ether epoxy-p-methane;

acid amides such as acetamide, benzamide and toluylic acid amide;

amines such as methylamine, ethylamine, diethylamine, tributylamine,piperidine, tribenzylamine, aniline, pyridine, picoline andtetramethylenediamine; and

nitriles such as acetonitrile, benzonitrile and tolunitrile. Theseelectron donors as exemplified above may be used either singly or incombination of two or more. Of these electron donors, preferred areorganic acid esters particularly aromatic carboxylic acid esters. It isnot always necessary to use these electron donors as startingsubstances, and they can also be formed in the course of a process forthe preparation of the solid titanium catalyst component [A]. Theseelectron donors may also be used in the form of addition compound orcomplex compound with other compounds.

The solid titanium catalyst component [A] can be obtained (a) bybringing the above-mentioned liquid magnesium compound (i) having noreducing ability into contact with the liquid titanium compound (ii) inthe presence of the electron donor (iii) having no active hydrogen.

This solid titanium catalyst component [A] may also be obtained (b) bybringing the above-mentioned (i) into contact with the above-mentioned(ii), followed by contact with the above-mentioned (iii).

In the procedure (a) mentioned above, when an electron donor has beencontained in the above-mentioned (i) and/or the above-mentioned (ii), nofurther addition of the electron donor (iii) is necessary when said (i)and (ii) are brought into contact with each other. However, it is alsopossible to add in advance the electron donor (iii) in the (i) and/orthe (ii), and said (i) and (ii) are brought into contact with each otherwhile further adding the (iii) thereto.

The electron donor (iii) may be contained in the liquid magnesiumcompound (i) by simply mixing it with the solution of said magnesiumcompound, or by previously adding said electron donor (iii) in advanceto the solvent in which the magnesium compound is dissolved.

For example, a hydrocarbon solution containing an alkylmagnesiumcompound having reducing ability, the reducing ability of which has beendisappeared by the addition of excess electron donor having no activehydrogen or reduced the reducing ability by the addition of a mixture ofan electron donor having active hydrogen and an electron donor having noactive hydrogen, is solubilized in a hydrocarbon solvent by theprocedure as mentioned previously. It is also possible in that case thatinstead of using the electron donor (iii) itself from the start, acompound capable of converting into the electron donor (iii) is used andallowed to undergo reaction in situ to form said electron donor (iii).

The amount of the electron donor (iii) used is 0.01-10 moles, preferably0.01-1 mole and especially 0.1-0.5 mole per mole of the magnesiumcompound used. Even when the electron donor is used in large amounts,the solid catalyst component of high performance is obtained if theamount of the titanium compound used is controlled, but the use of theelectron donor (iii) in such proportion as defined above.

The titanium compound in a liquid state (under contact conditions) is aliquid titanium compound in itself or a solution of the titaniumcompound in hydrocarbon. The electron donor (iii) or a compound capableof converting into the electron donor (iii) in a process of reaction maybe contained in this liquid titanium compound. In this case, however, itis preferable to use the titanium compound in large amount so that afree titanium compound which does not form a complex compound with theelectron donor (iii) is present in the system. That is, it is desirableto use the titanium compound in an amount, based on 1 mole of theelectron donor (iii), in excess of 1 mole, preferably in the proportionof more than 5 moles. The amount of the titanium compound used must besufficient for forming a solid product thereof on contact withoutapplying a special separation means, and accordingly when the amount ofthe titanium compound used is small, no precipitation occur by thecontact between the two. The amount of the titanium compound to be used,through it varies according to the kind thereof, contact conditionsemployed or to the amount of the electron donor used, is more than about1 mole, usually from about 5 to about 200 moles and preferably fromabout 10 to about 100 moles. The titanium compound is preferably used inan amount, based on 1 mole of the electron donor (iii), of more thanabout 1 mole, preferably more than about 5 moles.

In preparing the solid titanium catalyst component [A], the liquidmagnesium compound (i) having no reducing ability and the liquidtitanium compound are brought into contact with each other by any of theaforementioned procedures for mixing the magnesium compound with theliquid titanium compound. In this case, the resulting solid titaniumcatalyst component sometimes varies in shape or size according to thecontact conditions employed. Of the procedures as aforementioned,preferred is a procedure wherein the liquid titanium compound and theliquid magnesium compound are mixed together at such a sufficiently lowtemperature that a solid product is not formed rapidly by the contactbetween the two compounds, and the temperature is then elevated so thatthe solid product is formed gradually. According to this procedure, itis easy to obtain a granular solid catalyst component relatively largein particle diameter or a spherical solid catalyst component. In thisprocedure, moreover, when an appropriate amount of the electron donor(iii) having no active hydrogen is allowed to present in the system,there is obtained a granular or spherical solid catalyst componentfurther improved in particle size distribution. The polymer obtained bythe use of a catalyst containing such solid titanium catalyst componentas mentioned above is granular or spherical in shape, large in particlesize distribution and bulk density, and favorable in flowability. Theterm granular used herein is intended to mean the shape of a solidproduct as if it were formed by agglomeration of fine particles whenviewed from an enlarged photograph thereof. According to the process forpreparing the solid catalyst component employed, there can be obtainedsolid catalyst components in the shape of form granules having ruggedsurface to a true sphere.

The temperature at which the liquid titanium compound and the liquidmagnesium compound are brought into contact with each other is, forexample, a temperature of from about -70° to about +200° C. In thiscase, the two liquid compounds to be brought into contact with eachother may be different in temperature from each other. Generally, thesolid catalyst component having a favorable shape of granule or sphereand having a high performance is obtained in most cases by theaforementioned procedure wherein the liquid titanium compound and theliquid magnesium compound are brought into contact with each other at arelatively low temperature, for example, a temperature of from -70° to+50° C. In this case, the solid product will not be separated by thecontact of the two compounds when the contact temperature is low. Insuch a case, the solid product is allowed to separate by reaction at atemperature elevated to about 50° to about 150° C., or by prolonging thecontact time. The solid product thus separated is desirably washed atleast one time at a temperature of from about 50° to about 150° C. witha liquid titanium compound, preferably excess titanium tetrachloride.Thereafter, the solid titanium catalyst component thus obtained isusually washed with hydrocarbon and then used in the preparation of theolefin polymerization catalyst of the present invention.

This procedure is an excellent procedure since the solid catalystcomponent having high performance is obtained by simple operation.

In the aforementioned procedure (b), the solid titanium catalystcomponent [A] is prepared in the following manner.

A suspension containing a solid product is obtained by bringing theliquid magnesium compound into contact with the liquid titanium compoundunder the same conditions as employed in the procedure (a) mentionedpreviously. Generally, the electron donor (iii) is added to thesuspension and allowed to react therewith at a temperature, for example,from about 0° to about 150° C. The amount of the electron donor (iii)used in this case is the same as that used in the procedure (a).

Furthermore, the above-mentioned procedure (b) may also be used incombination with the procedure (a). According to this combinedprocedure, the shape and particle diameter of the resulting solidproduct can be adjusted to as desired by virtue of the procedure (a),and the micro-adjustment control of the resulting catalyst component canbe made. In one embodiment of this combined procedure, the liquidmagnesium compound and the liquid titanium compound are brought intocontact with each other in the coexistence of the electron donor (iii)to separate the solid product, and the thus separated solid product isfurther brought into contact with the electron donor (iii).

The solid titanium catalyst component [A] obtained by each procedure asmentioned above is thoroughly washed with and used for the preparationof the olefin polymerization catalyst of the present invention.

The solid titanium catalyst component [A] thus obtained desirably has amagnesium/titanium (atomic ratio) of usually about 2-100, preferablyabout 4-50 and especially about 5 to about 30, a halogen/titanium(atomic ratio) of usually about 4-100, preferably 5-90 and especiallyfrom about 8 to about 50, and an electron donor/titanium (molar ratio)of usually about 0.01-100, preferably from about 0.2 to about 10 andespecially about 0.4 to about 6.

As mentioned previously, this solid titanium catalyst component, in mostcases, is granular or almost spherical in shape, and has a specificsurface area of usually about more than 10 m² /g, preferably 100-1000 m²/g.

The organometallic compound catalyst component [B] is illustratedhereinafter.

Examples of the organoaluminum compound catalyst component [B] of ametal belonging to Group I to III in the periodic table includecompounds having at least one Al-carbon bond in the molecular, forexample, organoaluminum compounds represented by the following formula(i)

    R.sup.1.sub.m Al(OR.sup.2).sub.n H.sub.p X.sub.q           (i)

wherein R¹ and R² may be the same or different and representindependently a hydrocarbon group having normally 1 to 15 carbon atoms,preferably 1 to 4 carbon atoms; X is halogen; and m, n, p and q arenumbers satisfying 0<m≦3, 0≦n<3, 0≦p<3, 0≦q<3 and m+n+p+q=3;

complex alkyl compounds of aluminum with Group I metals of the periodictable, represented by the following formula (ii)

    M.sup.1 AlR.sup.1.sub.4                                    (ii)

wherein M¹ is Li, Na or K and R¹ is as defined above; and

dialkyl compounds of Group II or III metals represented by the followingformula

    R.sup.1 R.sup.2 M.sup.2                                    (iii)

wherein R¹ and R² are as defined above, and M² is Mg, Zn or Cd.

Examples of the organoaluminum compounds having the formula (i) include:

compounds having the general formula of R¹ _(m) Al(OR²)_(3-m) wherein R¹and R² are as defined above, and m is a number preferably satisfying1.5≦m≦3;

compounds having the general formula of R¹ _(m) AlX_(3-m) wherein R¹ andX are as defined above, and m is a number preferably satisfying 0<m<3;

compounds having the general formula of R¹ _(m) AlH_(3-m) wherein R¹ isas defined above, and m is a number preferably satisfying 2≦m<3; and

compounds having the general formula of R¹ _(m) Al(OR²)_(n) X_(q)wherein R¹, R² and X are as defined above, and m, n and q are numberssatisfying 0<m≦3, 0≦n<3, 0≦q<3 and m+n+q=3.

Concrete examples of the organoaluminum compounds having the formula (i)include

trialkylaluminum compounds such as triethylaluminum andtributylaluminum;

trialkenylaluminum compounds such as triisoprenylaluminum;

dialkylaluminum alkoxides such as diethylaluminum ethoxide anddibutylaluminum butoxide;

alkylaluminum sesquialkoxides such as ethylaluminum sesquiethoxide andbutylaluminum sesquibutoxide;

partially alkoxylated alkylaluminum compounds such as those having anaverage composition represented by, for example, the formula of R¹ ₂.5Al(OR²)₀.5 ;

dialkylaluminum halides such as diethylaluminum chloride,dibutylaluminum chloride and diethylaluminum bromide;

alkylaluminum sesquihalides such as ethylaluminum sesquichloride,butylaluminum sesquichloride and ethylaluminum sesquibromide;

partially halogenated alkylaluminum compounds such as alkylaluminumdihalides such as ethylaluminum dichloride, propylaluminum dichlorideand butylaluminum dibromide;

dialkylaluminum hydrides such as diethylaluminum hydride anddibutylaluminum hydride;

partially hydrogenated alkylaluminum compounds such as alkylaluminumdihydride, for example, ethylaluminum dihydride and propylaluminumdihydride; and

partially alkoxylated and halogenated alkylaluminum compounds such asethylaluminum ethoxychloride, butylaluminum butoxychloride andethylaluminum ethoxybromide.

Furthermore, the organoaluminum compounds similar to the above-mentionedcompounds represented by formula (i) include organoaluminum compounds inwhich two or more aluminum atoms are bonded together via, for example,an oxygen atom or a nitrogen atom. Concrete examples of such compoundsare as follows:

    (C.sub.2 H.sub.5).sub.2 AlOAl(C.sub.2 H.sub.5).sub.2,

    (C.sub.4 H.sub.9).sub.2 AlOAl(C.sub.4 H.sub.9).sub.2,

and ##STR1##

Examples of the organoaluminum compounds having the formula (ii) include

    LiAl(C.sub.2 H.sub.5).sub.4,

    and

    LiAl(C.sub.7 H.sub.15).sub.4.

Among the above-exemplified compounds, particularly preferred aretrialkylaluminum compounds and alkylaluminum compounds in which two ormore aluminum compounds are bonded together.

Examples of the compound represented by the above-mentioned formula (3)are diethylzinc and diethylmagnesium. Further, alkylmagnesium halidessuch as ethylmagnesium chloride is also usable.

Of the compounds represented by the above-mentioned formulas (1), (2)and (3), respectively, particularly preferred are trialkylaluminum,alkylaluminum halides or mixtures thereof.

Polymerization of olefin with the olefin polymerization catalystcontaining the above-mentioned components [A] and [B] in the presentinvention is not limited only to copolymerization of ethylene andpentene-1, but it also includes copolymerization of three or morecomponents, for example, ethylene, pentene-1 and small amounts of otherα-olefins or polyenes copolymerizable therewith. The other α-olefinsusable in this copolymerization include, for example, 2-methylpropylene,1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-octene,1-nonene, 1-decene, 1-undecene, and 1-dodecene. Further, the polyenesinclude, for example, butadiene, isoprene, 1,4-hexadiene,dicyclopentadiene and 5-ethylidene-2-norbornene.

In the process for the preparation of the first ethylene/pentene-1copolymer according to the present invention, ethylene and pentene-1 arecopolymerized with the above-mentioned catalyst by vapor phasepolymerization.

The vapor phase polymerization of ethylene and pentene-1 is carried outusing a polymerizer equipped with a fluidized bed reactor or a stirringfluidized bed reactor. In this case, the solid titanium catalystcomponent [A] is used, as it is, or used as a suspension thereof in ahydrocarbon medium or olefin, and the organometallic compound catalystcomponent [B], either diluted or not diluted, is fed to thepolymerization system.

Further, the molecular weight of the resulting polymer can be modifiedby the addition of hydrogen to the polymerization system.

In the present invention, it is preferably to use a pre-polymerizedcatalyst. In carrying out the pre-polymerization, the above-mentionedelectron donor catalyst component may be present in the system inaddition to the above-mentioned catalyst component [A] andorganometallic compound catalyst component [B]. In that case, theelectron donor catalyst component may be used in an amount, based on 1gram atom of titanium of the titanium catalyst component [A], of 0.01-30moles, preferably 0.1-10 moles and especially 0.5-5 moles. In thepre-polymerization, α-olefin of 2-10 carbon atoms is pre-polymerized inan inert hydrocarbon solvent, using a liquid monomer as a solvent orwithout using any solvent. It is preferable, however, to carry out thepre-polymerization in the inert hydrocarbon solvent.

The amount of the α-olefin polymer resulting from the pre-polymerizationis, based on 1 g of the titanium catalyst component, 0.5-5000 g,preferably 1-1000 g and especially 3-200 g.

The inert hydrocarbon solvent used in the pre-polymerization includesaliphatic hydrocarbons such as propane, butane, n-pentane, isopentane,n-hexane, isohexane, n-heptane, n-octane, isooctane, n-decane,n-dodecane and kerosin; alicyclic hydrocarbons such as cyclopentane,methylcyclopentane, cyclphexane and methylcyclohexane; aromatichydrocarbons such as benzene, toluene and xylene; and halogenatedhydrocarbons such as methylene chloride, ethyl chloride, ethylenechloride and chlorobenzene, and of these hydrocarbons exemplified above,preferred are aliphatic hydrocarbons, particularly those of 3-10 carbonatoms.

In the case that non-active solvent or liquid monomer is used in thepre-polymerization, the amount of the solid titanium catalyst componentis, in the term of titanium atom, 0.001 to 500 mmol, preferably 0.005 to200 mmol per 1 liter solvent, and the organoaluminum compound [B] isused in an amount that Al/Ti (atomic ratio) of 0.5 to 500, preferably1.0 to 50, and especially 2.0 to 20.

The α-olefin used in the pre-polymerization includes those of not morethan 10 carbon atoms such as ethylene, propylene, 1-butene, 1-pentene,4-methyl-1-pentene, 3-methyl-1-pentene, 1-heptene, 1-octene and1-decene. Of these α-olefins, preferred is ethylene. In carrying out thepre-polymerization, these α-olefins may be homopolymerized on thecatalyst component or may be copolymerized thereon so long as thepolymer to be prepared using this pre-copolymerized catalyst componentis a crystalline polymer.

The polymerization temperature employed in the pre-polymerization variesaccording to the kind of α-olefin used or to the kind of an inerthydrocarbon solvent used, and cannot be defined indiscriminately.Generally, however, the polymerization temperature is from -40° to 80°C., preferably from -20° to 40° C. and especially from -10° to 30° C.

In the pre-polymerization, hydrogen may coexist with the polymerizationsystem.

In the present invention, copolymerization of ethylene and pentene-1 iscarried out using preferably the pre-polymerized catalyst as mentionedabove. In the copolymerization of ethylene and pentene-1, theethylene/pentene-1 copolymer is prepared so as to amount to1,000-100,000 g, preferably 2,000-50,000 g and especially 3,000-30,000 gper 1 gram of the titanium catalyst component [A] contained in theaforesaid catalyst on which α-olefin has been pre-polymerized.

The amount, based on 1 gram atom of titanium in the titanium catalystcomponent [A], of the organometallic compound catalyst component [B]used in the pre-polymerized catalyst is 1-1000 moles, preferably 3-500moles and especially 5-100 moles. In that case, other compounds such asan electron donor catalyst component may be used, and the amount, basedon 1 gram atom of the metallic atom in the organometallic compoundcomponent [B], of the electron donor catalyst component is not more than100 moles, preferably not more than 1 mole and especially from 0.001 to0.1 mole.

In the copolymerization mentioned above, the polymerization temperatureemployed is 20°-130° C., preferably 50°-120° C. and especially 70°-110°C., and the polymerization pressure is 1-50 kg.cm², preferably 2-30kg/cm² and especially 5-20 kg/cm². Further, an inert gas such asmethane, ethane, propane, butane or nitrogen may suitably injected intothe polymerization system so as to maintain a vaporous condition insidethe system.

In the present invention, the polymerization may be carried out by anyof the batchwise, semi-continuous and continuous methods.

The second ethylene/pentene-1 copolymer of the present invention is nowillustrated hereinafter.

The second ethylene/pentene-1 copolymer of the invention is a randomcopolymer obtained by vapor phase copolymerization of ethylene andpentene-1 in the presence of an olefin polymerization catalyst. Thesecond ethylene/pentene-1 copolymer of the invention may be furthercopolymerized, in the same manner as in the case of the firstethylene/pentene-1 copolymer of the invention, with small amounts ofother α-olefins or polyenes.

The second ethylene/pentene-1 copolymers of the present invention have amelt flow rate (MFR) of 0.01 to 100 g/10 min, preferably 0.05 to 50 g/10min as measured according to ASTM D 1238E.

The second ethylene/pentene-1 copolymers of the present invention have adensity of 0.88 to 0.95 g/cm³, preferably 0.89 to 0.94 g/cm³.

The second ethylene/pentene-1 copolymers of the present inventioncomprise 2 to 25% by weight, preferably 4 to 23% by weight, particularlypreferably 6 to 20% by weight of a constitution unit derived frompentene-1 and 75 to 98% by weight, preferably 77 to 96% by weight,particularly preferably 80 to 94% by weight of a constitution unitderived from ethylene.

The second ethylene/pentene-1 copolymers may contain not more than 10%by weight, preferably not more than 5% by weight, particularlypreferably not more than 3% by weight of a constitution unit derivedfrom one or more α-olefins or polyenes in addition to ethylene andpentene-1 as mentioned above.

The DSC melt-peak pattern of ultra-slowly cooled sample of the secondethylene/pentene-1 copolymer of the present invention has two melt-peaksand the relationship between the ratio of Hh/Hl (wherein Hh is a peakheight on the higher temperature side and Hl is a peak height on thelower temperature side) and the density (d) of the copolymer fulfillsthe following formula [6].

    60d-52.0<Hh/Hl<80d-69.0                                    [6]

Preferably,

    60d-52.0<Hh/Hl<80d-69.1                                    [6']

Particularly preferably,

    60d-51.9<Hh/Hl<80d-69.2                                    [6"]

wherein Hh represents a peak height on the higher temperature side, Hlrepresents a peak height on the lower temperature side, and d is thedensity of the copolymer.

The ratio (RS) of the impact strength of a film of 40 μm in thickness tothe tear strength thereof in the take-off direction is represented bythe following formula [7], said film being obtained by casting theethylene/pentene-1 copolymer having the above-mentioned characteristicsaccording to the present invention.

    RS≧-20 log MFR-1000d+968                            [7]

wherein MFR is the melt flow rate of the copolymer and d is the densityof the copolymer.

Preferably,

    RS≧-20 log MFR-1000d+973                            [7']

Particularly preferably,

    200≧RS≧-20 log MFR-1000d+975                 [7"]

When the ratio (RS) of the impact strength to the tear strength is lowerthan (-20 log MFR-1000d+968), the resulting film has poor tearproperties, though it has a high impact strength, or the resulting filmis inferior in impact strength, though it has good tear properties. Thefilm of 40 μm in thickness, used for the measurement of the RS value, isa film prepared by molding the ethylene/pentene-1 copolymer under thefollowing conditions into a film by using a T-die film molding machineequipped with a 65 mmΦ extruder.

Molding conditions:

Resin temperature: 220° to 240° C.

Chill roll temperature: 30° to 40° C.

Film-forming rate: 20 to 30 m/min

Draft ratio (film thickness/lip opening): 0.05 to 0.07

The cast film of 40 μm in thickness, obtained by processing thecopolymer of the present invention in the manner mentioned above has animpact strength of generally not lower than 1000 kg·cm/cm, preferablynot lower than 1200 kg·cm/cm.

It is preferred that the tear strength (T_(MD)) of said film in thetake-off direction and the melt flow rate (MFR) of theethylene/pentene-1 copolymer fulfills the relationship represented bythe following formula [8].

    Log T.sub.MD ≦-0.37 log MFR-5.1d+6.72               [8]

wherein d is the density of the copolymer.

Preferably,

    Log T.sub.MD ≦-0.37 log MFR-5.1d+6.65               [8']

Particularly preferably,

    Log T.sub.MD ≦-0.37 log MFR-5.1d+6.59               [8"]

Films excellent in impact strength as well as tear properties can beobtained from the ethylene/pentene-1 copolymers which fulfills therelationship represented by the above formula [8] with respect to thetear strength (T_(MD)) of the film in the take-off direction and MFR.

Pressed sheets of 2 mm in thickness obtained by molding theethylene/pentene-1 copolymers of the present invention as mentionedabove according to ASTM D 1928 have stress cracking resistance [SCresistance (ESCR), measured according to ASTM D 1692, antalocks 100%,50° C.] of at least 10 hr and satisfy the relationship represented bythe following formula [9-a].

    ESCR≧0.7×10.sup.4 (log 80-log MFR).sup.3 (0.952-d)[9-a]

wherein 2.0≦MFR≦50 and d is the density of the copolymer.

Preferably,

    ESCR≧0.9×10.sup.4 (log 80-log MFR).sup.3 (0.952-d)[9'-a]

Particularly,

    ESCR≧1.1×10.sup.4 (log 80-log MFR).sup.3 (0.952-d)[9"-a]

Further, pressed sheets of 2 mm in thickness, obtained by molding theethylene/pentene-1 copolymers of the present invention according to ASTMD 1928 have stress cracking resistance [SC resistance (ESCR), measuredaccording to ASTM D 1692, antalocks 10%, 50° C.] of at least 20 hr andsatisfy the relationship represented by the following formula [9-b].

    ESCR≧1.4×10.sup.4 (log 40-log MFR).sup.2 (0.952-d)[9-b]

wherein 1.0≦MFR≦20 and d is the density of the copolymer.

Preferably,

    ESCR≧1.7×10.sup.4 (log 40-log MFR).sup.2 (0.952-d)[9'-b]

Particularly preferably,

    ESCR≧2.0×10.sup.4 (log 40-log MFR).sup.2 (0.952-d)[9"-b]

Furthermore, pressed sheets of 2 mm in thickness, obtained by moldingthe ethylene/pentene-1 copolymers of the present invention according toASTM D 1928 have stress cracking resistance [SC resistance (ESCR),measured according to ASTM D 1692, antalocks 10%, 60° C.] of at least 50hr and satisfy the relationship represented by the following formula[9-c].

    ESCR≧0.50×10.sup.4 (log 100-log MFR) (0.952-d)[9-c]

wherein 0.1≦MFR≦5 and d is the density of the copolymer.

Preferably,

    ESCR≧0.65×10.sup.4 (log 100-log MFR) (0.952-d)[9'-c]

Particularly preferably,

    ESCR≧0.80×10.sup.4 (log 100-log MFR) (0.952-d)[9"-c]

Moreover, it is preferred that the haze of the above-mentioned pressedsheets and the melt flow rate (MFR) of the ethylene/pentene-1 copolymerssatisfy the relationship represented by the following formula [10].

    Log HAZE≧15d-0.45 log MFR-12.23                     [10]

wherein d is the density of the copolymer.

More preferably,

    Log HAZE≧15d-0.45 log MFR-12.26                     [10']

Particularly preferably,

    Log HAZE≧15d-0.45 log MFR-12.30                     [10"]

The press sheets of 2 mm in thickness, used for the measurements of theabove-mentioned physical properties were prepared from theethylene/pentene-1 copolymers according to ASTM D 1928.

The measurement of HAZE was made according to ASTM D 1003.

The second ethylene/pentene-1 copolymer of the invention as illustratedabove may be prepared by the second process for the preparation ofethylene/pentene-1 copolymer according to the invention as will bedetailed hereinafter.

In the process for the preparation of the second ethylene/pentene-1copolymer according to the invention, vapor phase copolymerization ofethylene and pentene-1 in the presence of such an olefin polymerizationcatalyst as will be mentioned below is included.

The olefin polymerization catalyst used in the process for thepreparation of the second ethylene/pentene-1 copolymer according to theinvention may include, for example, an olefin polymerization catalystcontaining a solid titanium catalyst component [A] for olefinpolymerization obtained by reaction of a hydrocarbon-insoluble solidmagnesium aluminum composite selected from (A₁) or (A₂) mentioned belowand a tetravalent titanium compound and containing at least titaniumatoms in a low valent state in the proportion of more than 10% andhaving OR group in an amount of from 1 to 15 in terms of OR/Mg (weightratio) and an organoaluminum compound catalyst component [B], said (A₁)representing a solid magnesium.aluminum composite having R¹ O group andR² group (R¹ and R² is each a hydrocarbon residue) obtained from aliquid magnesium compound formed from a mixture containing a magnesiumcompound and an electron donor or a liquid magnesium compound formedfrom a solution of a magnesium compound in hydrocarbon solvent, and said(A₂) representing a solid magnesium.aluminum composite containing R¹ Ogroup and R³ group (R³ is a hydrocarbon residue) obtained by reaction ofa solid magnesium compound (B) containing R¹ O group or R¹ OH groupobtained from a liquid magnesium compound formed from a mixturecontaining a magnesium compound and an electron donor or a liquidmagnesium compound formed from a solution of a magnesium compound inhydrocarbon solvent or the above-mentioned (A₁) with an organometalliccompound (C) of a metal belonging to the group I through III of theperiodic table.

Hereinafter, this olefin polymerization catalyst and the reaction systemusing said catalyst are illustrated. In this connection, however, theway of preparing the second ethylene/pentene-1 copolymer of theinvention is not limited only to the catalyst and reaction system usingthe same as will be illustrated below, but said copolymer can beprepared by using other catalysts or other reaction systems.

The above-mentioned olefin polymerization solid titanium catalystcomponent [A] is typically a component carrying a low valent titaniumthereon obtained by reaction of a magnesium.aluminum composite having R¹O group and a hydrocarbon residue obtained by reaction among a liquidmagnesium compound as a starting material, an organoaluminum compound, aR¹ O group (R¹ is a hydrocarbon residue) forming compound and optionallyother reaction reagent with a tetravalent titanium compound.

The liquid magnesium compound used above may be, for example, a solutionof the magnesium compound in hydrocarbon, electron donor or mixturethereof, or may be a melt of the magnesium compound. The magnesiumcompound used for this purpose includes halogenated magnesium such asmagnesium chloride, magnesium bromide, magnesium iodide or magnesiumfluoride; alkoxy magnesium halide such as methoxy magnesium chloride,ethoxy magnesium chloride, isopropoxymagnesium chloride, butoxymagnesium chloride or octoxy magnesium chloride; aryloxy magnesiumhalide such as phenoxy magnesium chloride or methylphenoxy magnesiumchloride; alkoxy magnesium such as ethoxy magnesium, isopropoxymagnesium, butoxy magnesium or octoxy magnesium; aryloxy magnesium suchas phenoxy magnesium or dimethylphenoxy magnesium; and magnesiumcarboxylate such as magnesium laurate or magnesium stearate. Themagnesium compounds used herein may also be complex or compositecompounds of the above-mention magnesium compounds with other metals, ormixtures thereof. Further, the magnesium compounds used herein may alsobe mixtures of two or more of these compounds exemplified above.

Of these magnesium compounds exemplified above, preferred are thoserepresented by MgX₂, Mg(OR⁵)X or Mg(OR⁵)₂ wherein X is halogen and R⁵ isa hydrocarbon residue) such as halogenated magnesium, alkoxy magnesiumhalide, aryloxy magnesium halide, alkoxy magnesium or arloxy magnesium.Of the halogen containing magnesium compounds, preferred are magnesiumchloride, alkoxy magnesium halide and aryloxy magnesium halide, andespecially preferred is magnesium chloride.

The liquid magnesium compound mentioned above is suitably a solution ofsaid magnesium compound in a hydrocarbon solvent or an electron donor,in which said magnesium compound is soluble, or in a mixture thereof.The hydrocarbon solvent used for this purpose includes aliphatichydrocarbons such as pentene, hexane, heptane, octane, decane, dodecane,tetradecane and kerosine; alicyclic hydrocarbons such as cyclopentane,methylcyclopentane, cyclohexane, methylcyclohexane, cyclooctane andcyclohexene; aromatic hydrocarbons such as benzene, toluene, xylene,ethylbenzene, cumene and cymene; and halogenated hydrocarbons such asdichloroethane, dichloropropane, trichloroethylene, carbon tetrachlorideand chlorobenzene.

The solution of the magnesium compound in the hydrocarbon solvent may beobtained by various methods, though they vary according to the kind ofthe magnesium compound and the solvent used, such as a method whereinthe two compounds are simply mixed together (for example using Mg(OR⁵)₂in which R⁵ is a hydrocarbon residue having 6-20 carbon atoms as themagnesium compound), and a method wherein the magnesium compound ismixed with the hydrocarbon solvent in the presence of an electron donorin which said magnesium compound is soluble, for example, alcohol,aldehyde, amine, carboxylic acid or a mixture thereof, or a mixturecomprising said mixture and other electron donor, and the resultingmixture is heated if necessary. For example, when a halogen containingmagnesium compound is dissolved in the hydrocarbon solvent usingalcohol, the amount of the alcohol used, though it varies according tothe kind and amount of the hydrocarbon solvent used and to the kind ofmagnesium compound used, is preferably more than about 1 mole, suitablyfrom about 1 to about 20 moles, more suitably from about 1.5 to about 12moles, per 1 mole of the halogen containing magnesium compound. When analiphatic hydrocarbon and/or an alicyclic hydrocarbon is used as thehydrocarbon solvent in the above case, alcohol is used in the proportionas defined above, wherein the halogen containing magnesium compound canbe solubilized by the use of a relatively small amount of the alcohol,for example, using alcohol having more than 6 carbon atoms incombination with said alcohol in an amount, based on 1 mole of thehalogen containing magnesium compound, of more than about 1 mole,preferably more than about 1.5 moles, and the resulting catalystcomponent comes to have a good shape. For example, when alcohol havingnot more than 5 carbon atoms is used alone in the above case, it isnecessary to use more than about 15 moles of the alcohol per mole of thehalogen containing magnesium compound, and no shape of the resultingcatalyst component is comparable to that of the catalyst componentobtained in the above case. On the one hand, the halogen containingmagnesium compound becomes soluble in an aromatic hydrocarbon by the useof alcohol in such an amount as defined above, irrespective of the kindof the alcohol used.

The halogen containing magnesium compound and alcohol are brought intocontact with each other in a hydrocarbon solvent at a temperature aboveroom temperature and, according to the kind of the alcohol andhydrocarbon solvent used, at a temperature of higher than about 65° C.,suitably about 80°-300° C. and more suitably from about 100° to about200° C. for a period of from about 15 minutes to about 5 hours,preferably from about 30 minutes to about 2 hours.

Preferable as the alcohol used in that case are those having not lessthan 6 carbon atoms, for example, aliphatic alcohol such as2-methylpentanol, 2-ethylpentanol, n-heptanol, n-octanol,2-ethylhexanol, decanol, dodecanol, tetradecyl alcohol, undecenol, oleylalcohol or stearyl alcohol; alicyclic alcohol such as cyclohexanol ormethylcyclohexanol; aromatic alcohol such as benzyl alcohol,methylbenzyl alcohol, α-methylbenzyl alcohol or α,α-dimethylbenzylalcohol; alkoxy-containing aliphatic alcohol such as n-butyl cellosolveor 1-butoxy-2-propanol. Examples of other alcohol include those havingnot more than 5 carbon atoms such as methanol, ethanol, propanol,butanol, ethylene glycol and methylcarboitol.

The magnesium compound may also be dissolved in an electron donor otherthan alcohol. Preferred examples of the electron donor used in this caseinclude amine, aldehyde and carboxylic acid, and examples of an electrondonor other than those mentioned above include phenol, ketone, ester,ether, amide, acid anhydride, acid halide, nitrile and isocyanate. Themagnesium compound may be dissolved in the electron donor as exemplifiedabove under the conditions similar to those employed in the case ofdissolving the magnesium compound in the hydrocarbon solvent using theelectron donor. In this case, however, the system must be maintained ata relatively high temperature and, therefore, from the technicalviewpoint of the preparation of catalyst, the catalyst component of highperformance is easily obtained when the solution of the magnesiumcompound in the hydrocarbon solvent is used.

Examples of the liquid magnesium compound include melts of the magnesiumcompounds. A typical example of the melts is, for example, a melt of acomplex of halogenated magnesium with such an electron donor asexemplified previously. Suitable as the melt referred to herein is amelt of a halogenated magnesium.alcohol complex represented by MgX₂ nR¹OH (R¹ is a hydrocarbon residue, and n is a positive number).

Stated below is the process for the preparation of a solid magnesiumaluminum composite having R¹ O group and R³ group (or R² group) (R¹, R²and R³ are each a hydrocarbon residue, and R³ (or R²) is a reducinggroup bonded directly to magnesium of aluminum atom) from the liquidmagnesium compound. The magnesium aluminum composite referred to hereinis represented by the empirical formula Mg_(a) Al_(b) R² _(c) (or R³ c)(OR¹)_(d) X² _(e) wherein X² is halogen, and 2a+3b=c+d+e. Under certaincircumstances, other compounds or electron donors may be bonded to thiscomplex. In this magnesium aluminum complex represented by theabove-mentioned empirical formula, Al/Mg (atomic ratio) is 0.05-1,preferably 0.08-0.5 and especially 0.12-0.3, R¹ O group is in an amount,based on 1 part by weight of magnesium, of 0.5-15 parts by weight,preferably 1-10 parts by weight and especially 2- 6 parts by weight, thehydrocarbon residue R² (or R³) is in an amount, based on 1 magnesiumatom, of 0.01-0.5 equivalent, preferably 0.03-0.3 equivalent andespecially 0.05-0.2 equivalent, and X² /Mg (atomic ratio) is 1-3,preferably 1.5-2.5.

The process for the preparation of the above-mentioned magnesiumaluminum composite is illustrated below in details.

The magnesium aluminum composite is prepared by a process wherein theliquid magnesium compound and an organoaluminium compound are broughtinto contact with each other to obtain directly said composite.

In this process, at least one of the liquid magnesium compound andorganoaluminum compound used is a compound having R¹ O group or R¹ Ogroup forming compound, e.g. a compound having R¹ OH group and, at thesame time, a halogen compound must be used.

For example, the desired magnesium composite may be obtained by thereaction between MgX₂ and alcohol, preferably the reaction between thesolution of the magnesium compound containing a hydrocarbon and analkylaluminum compound, or the reaction between Mg(OR⁵)X or Mg(OR⁵)₂ andalcohol, preferably by the reaction between the solution of themagnesium compound containing a hydrocarbon or a solution of Mg(OR⁵)₂ ina hydrocarbon and alkylaluminum halide.

The alkylaluminum compound referred to above includes trialkylaluminumsuch as triethylaluminum or tributylaluminum; trialkenylaluminum such astriisoprenylaluminum; dialkylaluminum alkoxide such as diethylaluminumethoxide or dibutylaluminum butoxide; alkylaluminum sesquialkoxide suchas ethylaluminum sesquiethoxide or butylaluminum sesquibutoxide;alkoxylated alkylaluminum having an average composition represented byR¹ ₂.5 Al(OR²)₀.5 ; dialkylaluminum halide such as diethylaluminumchloride, dibutylaluminum chloride or diethylaluminum bromide;alkylaluminum sesquihalide such as ethylaluminum sesquichloride,butylaluminum sesquichloride or ethylaluminum sesquibromide; partiallyhalogenated alkylaluminum such as alkylaluminum dihalide, for example,ethylaluminum dichloride, propylaluminum dichloride or butylaluminumdibromide; dialkylaluminum hydride such as diethylaluminum hydride ordibutylaluminum hydride; partially hydrogenated alkylaluminum such asalkylaluminum dihydride, for example, ethylaluminum dihydride orpropylaluminum dihydride; and partially alkoxylated and halogenatedalkylaluminum such as ethylaluminum ethoxychloride, butylaluminumbutoxychloride or ethylaluminum ethoxybromide.

Further, alkylaluminum halide may be selected from among the halogencontaining alkylaluminum compounds as exemplified above.

The process for the preparation of the magnesium aluminum composite asillustrated above includes not only a process which comprises bringingthe liquid magnesium compound into contact with the alkylaluminumcompound in one stage as aforesaid, but also a process which involves amulti-stage contact between the liquid magnesium compound and thealkylaluminum compound, wherein said liquid magnesium compound is firstbrought into contact with part of said alkylaluminum compound to form asolid magnesium compound, followed by further contact of said solidmagnesium compound with an alkylaluminum compound which is the same asor different from the alkylaluminum compound first used. Usually, of thetwo processes mentioned above, the latter is better than the former,because a particle diameter of the resulting composite or the amount oforganic group contained therein can easily be adjusted, and eventuallyit becomes easy to obtain the desired catalyst of high performance.

In the process involving such a multi-stage contact as mentioned above,it is also possible that after completion of the first-stage contact,the solid magnesium compound formed thereby is separated from the liquidsystem, and the thus separated solid magnesium compound proceeds to thesubsequent reaction in the second stage-contact.

Eventually, it is desirable to design that the solid magnesium aluminumcomposite obtained by the above-mentioned processes will come to havesuch composition as defined previously. For this purpose, it ispreferable to use the alkylaluminum compound in an appropriate amount atthe time of effecting the above-mentioned contact between the liquidmagnesium compound and said alkylaluminum compound. For example, in theprocess involving the multi-stage contact as aforesaid, when a solutionusing alcohol is used as the liquid magnesium compound, thealkylaluminum compound is used in such an amount that R² --Al bond ofsaid alkylaluminum compound is more than 0.5 equivalent based on 1equivalent of the hydroxyl group of said alcohol. When the amount of thealkylaluminum compound used is excessively large, the resulting solidcomponent deteriorates in shape, and no granular composite is obtainedsometimes. On that account, the alkylaluminum compound is used in suchan amount, based on 1 equivalent of the hydroxyl group of the alcohol,of 0.5-10 equivalent, preferably 0.7-5 equivalent, further preferably0.9-3 equivalent and especially 1.0-2 euivalent in terms of R² --Albond.

In that case, it is preferable to use trialkylaluminum as thealkylaluminum compound, because the solid composite having a good shapeis easy to obtain. Other preferred organoaluminum compounds aredialkylaluminum halide, dialkylaluminum hydride and dialkylaluminumalkoxide.

In the contact between the liquid magnesium compound and alkylaluminumcompound, the concentration in the liquid system of the magnesiumcompound is 0.005-2 mol/l, especially 0.05-1 mol/l.

Separation of the magnesium compound takes place, for example, aninsoluble magnesium compound is formed by the reaction of alkylaluminumcompound with alcohol. When the separation of the magnesium compoundproceeds so rapidly, it is sometimes difficult to obtain the solidcomposite excellent in shape and having an appropriate particle diameterand a narrow particle size distribution, accordingly the thus separatedsolid composited cannot sometimes be the optimum carrier for slurrypolymerization catalyst. On that account, it is desirable that theabove-mentioned contact is effected under mild conditions, takingaccount of the contact temperature, the amount of the alkylaluminumcompound added at the time of separation of the solid or the rate ofaddition of the alkylaluminum compound or concentration of each compoundused.

From the reasons cited above, it is preferable to effect the contact ofthe liquid magnesium compound with the organoaluminum compound at atemperature of from -50° to 100° C., especially from -30° to 50° C.,followed by reaction at a temperature of from 0° to 200° C., preferablyfrom 40° to 150° C. When the solid magnesium compound is first formed,and the solid magnesium compound thus formed is then brought intocontact with the alkylaluminum compound to effect the reaction asaforesaid, the reaction temperature employed therefor is from 0° to 250°C., especially from 20° to 130° C.

In either case, the contact and reaction conditions employed are sodesigned that R0 group and R² group of the resulting solid magnesiumaluminum composite respectively come within the range as definedpreviously and, at the same time, it is also desirable to select theseconditions so that the resulting composite has a particle diameter ofmore than 1 μm, especially more than 5 μm but not more than 100 μm, aparticles size distribution of 1.0-2.0 in terms of geometric standarddeviation and said compound will come to have a spherical or granularshape.

Further, the solid magnesium aluminum composite may be prepared by usingan organometallic compound of a metal other than aluminum belonging tothe group I-III of the periodic table, for example, alkyllithium,alkylmagnesium halide or dialkylmagnesium, instead of the alkylaluminumcompound, with which the solid magnesium compound first separated isbrought into contact.

The solid magnesium aluminum composite may be prepared by otherprocesses than those mentioned previously, for example, a process inwhich a halogenation agent such as chlorine, hydrogen chloride silicontetrachloride or halogenated hydrocarbon is used in any stage where thealkylaluminum compound is used in the previously mentioned processes, aprocess in which a halogenation agent is used before or after the use ofthe alkylaluminum compound. These processes mentioned above are usefulin substitution of the process using alkylaluminum halide.

The process using the halogenation agent prior to the use of thealkylaluminum compound is useful as a means for forming a solidmagnesium compound containing R¹ O group or R¹ OH group from a liquidmagnesium compound, and the desired solid magnesium aluminum compositemay be prepared by reaction of the thus formed solid magnesium compoundwith the alkylaluminum compound. For example, the above-mentioned solidmagnesium compound may be prepared by reaction of MgX₂, Mg(OR⁵)X orMg(OR⁵)₂ with alcohol, preferably with a solution containing ahydrocarbon and the halogenation agent, or by reaction of hydrocarbonsolvent containing Mg(OR⁵)₂ with the halogenation agent. The solidmagnesium compound thus prepared is represented by the empirical formulaMgX_(2-q) (OR⁵)_(q).nR⁶ OH (0≦q<2, n≧0), and optionally forms acomposite with other compound component in some cases. In this process,the reactants are used in such a proportion that halogen will amount toabout 1-1000 equivalent per 1 atom of magnesium present in the magnesiumcompound. The reaction between the solid magnesium compound thusprepared and the alkylaluminum compound may be carried out in accordancewith the procedure of the last stage of the above-mentioned processinvolving the multi-stage contact between the solid magnesium compoundand the alkylaluminum compound.

The solid magnesium compound as mentioned above may also be prepared byother process than those illustrated above, in which the magnesiumcompound of the formula MgX_(2-q) (OR⁵)_(q).nR⁶ OH in a moled state issolidified by cooling, preferably said molten magnesium compound isdispersed in a hydrocarbon medium and then solidified by cooling.

In any of the processes mentioned above, it is preferable to select theseparation conditions under which the solid magnesium compound isseparated so that the resulting solid magnesium compound has a particlediameter of more than 1 μm, especially more than 5 μm but not more than100 μm, and a particle size distribution of 1.0-2.0 in terms ofgeometric standard deviation, and said compound will come to have aspherical or granular shape.

The amount of the reducing group R² or R³ contained in the solidmagnesium aluminum composite obtained by the processes mentioned aboveis determined in the following manner.

To a closed flask of about 200 ml capacity thoroughly purged with drynitrogen and charged with about 0.5 g of a solid magnesium aluminumcomposite is gradually added dropwise with stirring about 25 ml ofwater. After the lapse of about 20 minutes, the vapor phase and waterphase portion in the flask were respectively with drawn by means of amicrosyringe, followed by determination of the alkane concentration ofeach portion by gas chromatography. The measured value of the alkaneconcentration in each portion is multiplied by a value of the volume ofeach portion, and the products thus obtained were then combined toobtain a total amount of alkane formed. This total amount is regarded asthe total amount of the alkane formed by reaction of the alkyl grouppresent in said composite with water, and can be considered to be theamount of the reducing group present in said composite.

The thus obtained solid magnesium aluminum composite having R¹ O groupand the organic reducing group is brought into contact with atetravalent titanium compound used in such a proportion that Ti/Mg(atomic ratio) is less than 1, preferably 0.01-0.7 and especially0.04-0.5 to prepare a solid titanium compound. At least a part oftitanium supported on this compound has been reduced to a low valentstate, for example, three valences.

There are various tetravalent titanium compounds used for thepreparation of the solid titanium component [A], but usually used arethose represented by Ti(OR)_(g) X_(4-g) wherein R is a hydrocarbonresidue, X is halogen atom, and 0≦g≦4. More concretely, usefultetravalent titanium compounds include titanium tetrahalide such asTiCl₄, TiBr₄ TiI₄ ; alkoxy titanium trihalide such as Ti(OCH₃)Cl₃,Ti(OC₂ H₅)Cl₃, Ti(O n-C₄ H₉)Cl₃, Ti(OC₂ H₅)Br₃ or Ti(O-iso-C₄ H₉) Br₃ ;dialkoxy titanium dihalide such as Ti(OCH₃)₂ Cl₂, Ti(OC₂ H₅)Cl₂, Ti(On-C₄ H₉)₂ Cl₂ or Ti(OC₂ H₅)₂ Br₂ ; trialkoxy titanium monohalide such asTi(OCH₃)₄, Ti(OC₂ H₅)₄, Ti(O n-C₄ H₉)₄, Ti(O-iso-C₄ H₉)₄ orTi(O-2-ethylhexyl)₄. Of these tetravalent titanium compound asexemplified above, preferred are titanium tetrahalide and alkoxytitanium trihalide, and particularly the use of alkoxy titanium trihaldeis preferable.

The catalytic reaction of the solid magnesium aluminum composite withthe titanium compound is carried out preferably in a hydrocarbon mediumunder the conditions selected so that in the end solid titanium catalystcomponent resulting from the contact with the titanium compound, R⁷ Ogroup/Mg weight ratio (R⁷ is a hydrocarbon residue) is 0.05-15,preferably 1-10 and especially 2-6. Herein R⁷ O group is derived from R¹O group present in the solid magnesium aluminum composite or thetitanium compound. When the content of R⁷ O group in the solid catalystcomponent is smaller than the above-defined range, slurrypolymerizability in the copolymerization of ethylene is poor, andeventually the resulting ethylene copolymer comes to have not asufficiently narrow composition distribution. If the content of R⁷ Ogroup is larger than the above-defined range, catalyst component tendsto decrease in activity.

The content of R⁷ O group in the titanium catalyst component may beadjusted to the above-mentioned range by selecting the kind and amountof the titanium compound used and the temperature at which the contactof the solid magnesium aluminum composite and the titanium compound iseffected. The contact temperature at which the titanium compound isbrought into contact with the solid magnesium aluminum composite isusually about 0°-200° C., preferably about 20°-100° C.

In forming the above-mentioned solid product, a porous inorganic and/ororganic compound may be allowed to coexist with the starting reactantsin the reaction system, thereby depositing the resulting solid producton the surface of said porous compound. In this case, it is alsopossible that the porous compound is brought into contact in advancewith the liquid magnesium compound, and the porous compound containingand retaining said liquid magnesium compound is then brought intocontact with the liquid titanium compound. Examples of these usefulporous compounds include silica, alumina magnesia polyolefin and thesecompound treated with halogen containing compound. However, when aporous compound containing aluminum, magnesium and RO group which areessential components of the present catalyst component is used in theabove case, the resulting solid titanium catalyst will have sometimesthe composition deviating from the preferred catalyst composition asmentioned previously.

The titanium catalyst component thus obtained is represented by theempirical formula Mg_(r) Al_(s) Ti_(t) (OR⁷)_(u) X¹ _(v) wherein r, s,t, u, v>0, and X¹ is halogen, and may optionally contain other compoundssuch as a silicon compound. In this titanium catalyst component, Ti/Mg(atomic ratio) is usually 0.01-0.5, preferably 0.02-0.2, Al/Mg (atomicratio) is 0.05-1. preferably 0.08-0.5 and especially 0.12-0.3, X¹ /Mg(atomic ratio) is 1.5-3, preferably 2-2.5, OR⁷ /Mg (weight ratio) is0.5-15, preferably 1-10 and especially 2-6, and a specific surface areais 50-1000 m² /g, preferably 150-500 m² /g. Further, 10-100% of the allTi exhibits a valence lower than Ti⁴⁺.

The solid titanium catalyst component [A] as illustrated above may beused in combination with an organoaluminum compound catalyst component[B] in the polymerization of oelfin.

The organoaluminum compound catalyst component [B] mentioned above maybe selected from among the previously exemplified alkylaluminumcompounds which can be used in the preparation of the solid titaniumcatalyst component.

Of the alkylaluminum compounds referred to above, preferred aretrialkylaluminum and alkylaluminum halide or mixtures thereof.

Polymerization of olefin with an olefin polymerization catalystcontaining the solid component [A] and the component [B] as mentionedabove includes not only the copolymerization of ethylene and pentene-1but also the copolymerization of three or more components such asethylene, pentene-1 and small amounts of other α-olefins or polyenes.Other α-olefins than ethylene and pentene-1, which are useful in thiscopolymerization include 2-methyl-propylene, 1-butene, 1-hexene,4-methyl-1-pentene, 3-methyl-1-pentene, 1-octene, 1-nonene, 1-decene,1-undecene and 1-dodecene. Further, useful polyenes include butadiene,isoprene, 1,4-hexadiene, dicyclopentadine and 5-ethylidene-2-norbonene.

The above-mentioned olefin polymerization catalyst is usefulparticularly when ethylene and pentene-1 are copolymerized in the vaporphase.

The polymerization reaction is carried out in the vapor phase, and thisreaction can be carried out using a fluidized reactor, stirring bedreactor, stirring bed fluid reactor or tube reactor.

The solid titanium catalyst component [A] is used in powder form orafter suspending it in a hydrocarbon medium or olefin, and theorganoaluminum compound catalyst component [B] is fed to thepolymerization system after dilution with a proper diluent or fed, as itis, to said system.

Further, the molecular weight of the resulting polymer can be controlledby feeding hydrogen to the polymerization system.

In the present invention, it is preferably to use a pre-polymerizedcatalyst. In carrying out the pre-polymerization, the electron donorcatalyst component mentioned previously can be used in addition to thecatalyst component [A] and the organoaluminum compound [B]. In thatcase, the amount of the electron donor catalyst component used is0.01-30 moles, preferably 0.1-10 moles and more preferably 0.5-5 molesbased on 1 gram atom of titanium present in the titanium catalystcomponent [A]. The pre-polymerization is to polymerize α-olefin of 2-10carbon atoms on the catalyst in an inert hydrocarbon solvent, a liquidmonomer as a solvent or in the absence of any solvent, however, thepre-polymerization carried out in the inert hydrocarbon solvent ispreferred.

In the pre-polymerization, the amount of α-olefin polymerized is0.5-5000 g, preferably 1-1000 g and more preferably 3-200 g based on 1 gof the titanium catalyst component used.

The inert hydrocarbon solvent used in the pre-polymerization includesaliphatic hydrocarbons such as propane, butane, n-pentane, iso-pentane,n-hexane, iso-hexane, n-heptane, n-octane, isooctane, n-decane,n-dodecane and kerosine; alicyclic hydrocarbons such as cyclopentane,methylcyclopentane, cyclohexane and methylcyclohexane; aromatichydrocarbons such as benzene, toluene and xylene; and halogenatedhydrocarbons such as methylene chloride, ethyl chloride, ethylenechloride and chlorobenzene. Of these hydrocarbons as exemplified above,preferred are aliphatic hydrocarbons, particularyly those of 3-10 carbonatoms.

When the inert solvent or the liquid monomer as an inert solvent is usedin the pre-polymerization, the titanium catalyst component [A] is usedin an amount, per 1 liter of the solvent, of 0.001-500 mmoles,preferably 0.005-200 mmoles in terms of titanium atom, and theorganoaluminum compound [B] is used in such a proportion that Al/Ti(atomic ratio) is 0.5-500, preferably 1.0-50 and especially 2.0-20.

The α-olefin used in the pre-polymerization includes those having notmore than 10 carbon atoms such as ethylene, propylene, 1-butene,1-pentene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-heptene, 1-octeneand 1-decene, and of these α-olefins, ethylene is particularlypreferred. In carrying out the pre-polymerization, these α-olefins maybe homopolymerized independently, or two or more α-olefins may becopolymerized, so long as the resulting pre-polymerized catalyst isintended to prepare crystalline polymers.

The polymerization temperature employed in the pre-polymerization variesaccording to the kind of α-olefin and inert hydrocarbon solvent used andcannot be defined indiscriminately, but the temperature is commonly from-40° to 80° C., preferably from -20° to 40° C. and especially from -10°to 30° C.

In the pre-polymerization, hydrogen may be allowed to coexist in thepolymerization system.

Further, the pre-polymerization may be carried out by any of thebatchwise and continuous methos, but the continuous method is preferredwhen the pre-polymerization on a large scale is required.

In the present invention, it is preferably to carry out thecopolymerization of ethylene and pentene-1 with the aforementionedcatalyst which has been subjected to pre-polymerization. Thepre-polymerized catalyst may be fed in powder state to the vapor phasepolymerizer, or said catalyst suspended in a hydrocarbon solvent asaforesaid may be fed to the polymerizer. The pre-polymerized catalyst isdesirably suspended particularly in a low boiling solvent such aspropane, iso-butane, n-butane or iso-pentane. By carrying outcopolymerization of ethylene and pentene-1 with the olefinpolymerization catalyst containing the above-mentioned pre-polymerizedtitanium catalyst component [A], an ethylene/pentene-1 copolymer isprepared in an amount, based on 1 g of said titanium catalyst component,of 1,000-100,000 g, preferably 2,000-50,000 g and especially3,000-30,000 g.

In the olefin polymerization catalyst, the organoaluminum compoundcatalyst component [B] is used in an amount, based on 1 gram atom oftitanium present in the titanium catalyst component [A], of 1-1000moles, preferably 3-500 moles and especially 5-100 moles. Further, theolefin polymerization catalyst may also contain other compound, forexample, the electron donor catalyst component. In that case, theelectron donor catalyst component is used in an amount, based on 1 gramatom of the metal element present in the organoaluminum compoundcatalyst component [B], of not more than 100 moles, preferably not morethan 1 mole and especially 0.001-0.1 mole.

The copolymerization of ethylene and pentene-1 is carried out at thepolymerization temperature of 20°-130° C., preferably 50°-120° C. andespecially 70°-110° C. The polymerization pressure employed at that timeis 1-50 kg/cm², preferably 2-30 kg/cm² and especially 5-20 kg/cm².Further, an inert gas forming a gaseous state in the polymerizationsystem, such as methane, ethane, propane, butane or nitrogen, maysuitably fed to the polymerization system.

In carrying out the polymerization reaction, the solid titanium catalystcomponent [A] is used in an amount, based on 1 liter of the reactionvolume, of from 0.00001 to about 1 mmol, preferably from about 0.0001 toabout 0.1 mmole in terms of Ti atom.

The third ethylene/pentene-1 copolymer of the present invention is nowillustrated hereinafter.

The third ethylene/pentene-1 copolymer of the invention is a randomcopolymer obtained by copolymerization of ethylene and pentene-1 in asuspension state in the presence of the olefin polymerization catalystexemplified in the second process of the invention. The thirdethylene/pentene-1 copolymer of the invention may be furthercopolymerized, in the same manner as in the case of the first and secondethylene/pentene-1 copolymer of the invention, with small amounts ofother α-olefins or polyenes.

The third ethylene/pentene-1 copolymers of the present invention have amelt flow rate (MFR) of 0.01 to 100 g/10 min, preferably 0.05 to 50 g/10min as measured according to ASTM D 1238E.

The third ethylene/pentene-1 copolymers of the present invention have adensity of 0.90 to 0.96 g/cm³, preferably 0.91 to 0.95 g/cm³, morepreferably 0.92 to 0.94 g/cm³, as measured according to ASTM D 1505.

The third ethylene/pentene-1 copolymers of the present inventioncomprise 2 to 15% by weight, preferably 3 to 12% by weight, particularlypreferably 4 to 10% by weight of a constitution unit derived frompentene-1 and 85 to 98% by weight, preferably 88 to 97% by weight,particularly preferably 90 to 96% by weight of a constitution unitderived from ethylene.

The third ethylene/pentene-1 copolymers may contain not more than 5% byweight, preferably not more than 3% by weight, particularly preferablynot more than 2% by weight of a constitution unit derived from one ormore α-olefins or polyenes in addition to ethylene and pentene-1 asmentioned above.

The DSC melt-peak pattern of ultra-slowly cooled sample of the thirdethylene/pentene-1 copolymer of the present invention has two melt-peaksand the relationship between the ratio of Hh/Hl (wherein Hh is a peakheight on the higher temperature side and Hl is a peak height on thelower temperature side) and the density (d) of the copolymer fulfillsthe following formula [11].

    60d-52.0<Hh/Hl<80d-69.0                                    [11]

Preferably,

    60d-52.0<Hh/Hl<80d<69.1                                    [11']

Particularly preferably,

    60d<51.9<Hh/Hl<80d<69.2                                    [11"]

wherein Hh represents a peak height on the higher temperature side, Hlrepresents a peak height on the lower temperature side, and d is thedensity of the copolymer.

The ratio (RS) of the impact strength of a film of 40 μm in thickness tothe tear strength thereof in the take-off direction is represented bythe following formula [12], said film being obtained by casting theethylene/pentene-1 copolymer having the above-mentioned characteristicsaccording to the present invention.

    RS≧-20 log MFR-1000d+968                            [12]

wherein MFR is the melt flow rate of the copolymer and d is the densityof the copolymer.

Preferably,

    RS≧-20log MFR-1000d+973                             [12']

Particularly preferably,

    200≧RS≧-20log MFR-1000d+975                  [12"]

When the ratio (RS) of the impact strength to the tear strength is lowerthan (-20 log MFR-1000d+968), the resulting film has poor tearproperties, though it has a high impact strength, or the resulting filmis inferior in impact strength, though it has good tear properties. Thefilm of 40 μm in thickness, used for the measurement of the RS value, isa film prepared by molding the ethylene/pentene-1 copolymer under thefollowing conditions into a film by using a T-die film molding machineequipped with a 65 mmφ extruder.

Molding conditions:

Resin temperature: 220° to 240° C.

Chill roll temperature: 30° to 40° C.

Film-forming rate: 20 to 40 m/min

Draft ratio (film thickness/lip opening): 0.05 to 0.07

Other physical properties of the third ethylene/pentene-1 copolymer ofthe present invention, such as an impact strength, a tear strength(TMD)-melt flow rate (MFR) relationship, a stress crack resistance(ESCR) of the film resulting from said copolymer, and a haze (HAZE)-meltflow rate (MFR) relationship of said copolymer, are preferably similarto those of the second ethylene/pentene-1 copolymer of the invention.

The third ethylene/pentene-1 copolymer of the invention as illustratedabove may be prepared by the third process for the preparation of theethylene/pentene-1 copolymer according to the invention as will bementioned below in detail.

In the third process for the preparation of the ethylene/pentene-1copolymer according to the invention, ethylene and pentene-1 arecopolymerized using a catalyst, for example, the olefin polymerizationcatalyst used in the second process of the invention mentionedpreviously. The copolymerization of ethylene and pentene-1 in the thirdprocess of the invention is carried out preferably in the presence ofthe aforementioned pre-polymerized catalyst. In this copolymerization,it is preferable to use the titanium catalyst component [A] of thepre-polymerized catalyst in an amount, based on 1 liter of thepolymerization solvent, of from 0.0001 to about 1 mmole, preferably fromabout 0.001 to about 0.1 mmole in terms of Ti atom. Through thecopolymerization mentioned above, an ethylene/pentene-1 copolymer isprepared in an amount, based on 1 g of the titanium catalyst component[A], of 1000-100,000 g, preferably 2,000-50,000 g and especially3,000-30,000 g.

In that case, it is preferable to use the organoaluminum compoundcatalyst component [B] in an amount, based on 1 gram atom of titaniumpresent in the titanium catalyst component [A], of 1-1000 moles,preferably 3-500 moles and especially 5-100 moles. The pre-polymerizedcatalyst used may contain other compounds, for example, an electrondonor catalyst component in an amount, based on 1 gram atom of the metalelement present in the organoaluminum compound catalyst component [B],of not more than 100 moles, preferably not more than 1 mole andespecially 0.001-0.1 mole.

The polymerization temperature employed in this case is 20°-130° C.,preferably 50°-120° C. and especially 70°-110° C., and thepolymerization pressure is 1-50 kg/cm², preferably 2-30 kg/cm² andespecially 5-20 kg/cm². Further, an inert gas forming a gaseous state inthe polymerization system, such as methane, ethane, propane, butane ornitrogen, may suitably fed to the system.

In the third process for the preparation of the ethylene/pentene-1copolymer according to the invention, ethylene and pentene-1 arecopolymerized in a suspension state in the presence of an olefinpolymerization catalyst containing, for example, at least one solidcatalyst component as mentioned above, and the copolymerization reactionis carried out in the presence of a liquid medium used in an amount ofmore than the weight of the copolymer obtained in the steady state, andat the state where more than 30% by weight of said copolymer will not beeluted into said liquid medium.

The liquid medium referred to above, which is used in an amount of morethan the weight of the copolymer obtained in the steady state, isintended to designate a solvent used as a dispersant to disperse theabove-mentioned solid substance, for example, a catalyst supported by asolid carrier of a solid catalyst component, or used as a polymerizationreaction solvent. This liquid medium includes, for example, alphatichydrocarbon such as propane, iso-butane, n-butane, iso-pentane,n-pentane, iso-hexane, n-hexane, iso-heptane, n-heptane, iso-octane,n-octane, iso-decane, n-decane, dodecane or kerosine, and halogenderivatives thereof; alicyclic hydrocarbon such as cyclopentane,cyclohexane, methylcyclopentane, or methylcyclohexane, and halogenderivatives thereof; aromatic hydrocarbon such as benzene, toluene orxylene, and a halogen derivative thereof such as chlorobenzene.

The third process for the preparation of the ethylene/pentene-1copolymer according to the invention is carried out in the presence ofthe catalyst and liquid medium as mentioned above at such a state thatmore than 30% by weight, preferably 0-10% by weight of the copolymerobtained in the steady state will not be eluted into said liquid medium.

When the copolymerization reaction is carried out at the state wheremore than 30% by weight of the copolymer obtained in the steady statewill be eluted into the liquid medium, it becomes difficult to continuethe polymerization reaction without interruption.

The above-mentioned first, second and third ethylene/pentene-1copolymers having aforesaid properties are excellent in transparency,impact resistance, tear resistance, blocking resistance, low-temperatureheat sealing properties, heat resistance and stress crack resistance andthese excellent properties are well-balanced so that the copolymers aresuitable for use in the preparation of packaging films in particular. Inaddition to being used as packaging film materials, the copolymers canbe processed into various molded articles such as containers, articlesfor daily use, pipes and tubes by T-die molding, inflation molding, blowmolding, injection molding and extrusion. Further, the copolymers can beextrusion-coated on other film or co-extruded together with other filmto prepare various composite films. Furthermore, the copolymers can beused in the fields of steel pipe coating materials, wire coatingmaterials and expansion-molded articles. In addition, the copolymers canbe used as blends with other thermoplastic resins such as polyolefins,for example, high-density polyethylene, medium-density polyethylene,polypropylene, poly(1-butene), poly(4-methyl-1-pentene), low-crystallineto non-crystalline copolymers of ethylene and propylene or 1-butene andpropylene/1-butene copolymers.

If desired, heat stabilizers, weathering stabilizers, antistatic agents,anti-blocking agents, slip agents, nucleating agents, pigments, dyes andinorganic or organic fillers may be blended with the above-mentionedethylene/pentene-1 copolymers.

The ethylene/pentene-1 copolymer compositions of the present inventionare illustrated below.

The ethylene/pentene-1 copolymer compositions of the present inventioncomprise an ethylene/pentene-1 copolymer and at least the compoundselected from the group consisting of the following compounds (a) to(e).

(a) Phenolic stabilizer

(b) Organic phosphite stabilizer

(c) Thioether stabilizer

(d) Hindered amine stabilizer

(e) Metal salt of higher aliphatic acid.

As the ethylene/pentene-1 copolymers used in the compositions of thepresent invention, however it is not especially limited, the aforesaidfirst, second and third ethylene/pentene-1 copolymers are used. Theseethylene/pentene-1 copolymers are used singly or in combination.

The ethylene/pentene-1 copolymer used in the compositions according tothe present invention are preferably manufactured by the above-describedprocesses according to the present invention for preparing theethylene/pentene-1 copolymer.

The compositions according to the present invention comprise theabove-mentioned ethylene/pentene-1 copolymer and at least one compoundselected from the group consisting of the compounds denoted by (a) to(e) mentioned above.

These compounds are illustrated hereinafter.

Phenolic Stabilizers (a)

Though conventionally known phenolic compounds are used as phenolicstabilizers without specific restriction, concrete examples of thephenolic stabilizers include

2,6-di-tert-butyl-4-methylphenol,

2,6-di-tert-butyl-4-ethylphenol,

2,6-dicyclohexyl-4-methylphenol,

2,6-diisopropyl-4-ethylphenol,

2,6-di-tert-amyl-4-methylphenol,

2,6-di-tert-octyl-4-n-propylphenol,

2,6-dicyclohexyl-4-n-octylphenol,

2-isopropyl-4-methyl-6-tert-butylphenol,

2-tert-butyl-2-ethyl-6-tert-octylphenol,

2-isobutyl-4-ethyl-6-tert-hexylphenol,

2-cyclohexyl-4-n-butyl-6-isopropylphenol,

dl-α-tocopherol,

tert-butylhydroquinone,

2,2'-methylenebis(4-methyl-6-tert-butylphenol),

4,4'-butylidenebis(3-methyl-6-tert-butylphenol),

4,4'-thiobis(3-methyl-6-tert-butylphenol),

2,2-thiobis(4-methyl-6-tert-butylphenol),

4,4'-methylenebis(2,6-di-tert-butylphenol),

2,2'-methylenebis[6-(1-methylcyclohexyl)-p-cresol],

2,2'-ethylidenebis(2,4-di-tert-butylphenol),

2,2'-butylidenebis(2-tert-butyl-4-methylphenol),

1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane,

triethylene glycolbis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate],

1,6-hexanediol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate],

2,2'-thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate],

N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyhydrocinnamamide),

3,5-di-tert-butyl-4-hydroxybenzyl phosphonate diethyl ester,

1,3,5-tris(2,6-dimethyl-3-hydroxy-4-tert-butylbenzyl) isocyanurate,

1,3,5-tris[(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxyethyl]isocyanurate,

tris(4-tert-butyl-2,6-dimethyl-3-hydroxybenzyl) isocyanurate,

2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylanilino)-1,3,5-triazine,

tetrakis[methylene3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane,

bis(3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid ethyl ester)calcium,

bis(3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid ethyl ester)nickel,

bis[3,3-bis(3-tert-4-hydroxyphenyl)butyric acid] glycol ester,

N,N'-bis[(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine,

2,2'-oxamidobis[ethyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate],

2,2'-methylenebis(4-methyl-6-tert-butylphenol) terephthalate,

1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene,

3,9-bis[1,1-dimethyl-2-{β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane,

2,2-bis[4-(2-(3,5-di-tert-butyl-4-hydroxyhydrocinnamoyloxy))ethoxyphenyl]propane,and

alkyl esters of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid.

Of these compounds, preferred are

triethylene glycolbis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate],

1,6-hexanediol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate],

2,2-thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate],

N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyhydrocinnamamide),

3,5-di-tert-butyl-4-hydroxybenzyl phosphonate diethyl ester,

1,3,5-tris(2,6-dimethyl-3-hydroxy-4-tert-butylbenzyl) isocyanurate,

1,3,5-tris[(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxyethyl]isocyanurate,

tris(4-tert-butyl-2,6-dimethyl-3-hydroxybenzyl) isocyanurate,

2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylanilino)-1,3,5-triazine,

tetrakis[methylene3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane,

bis(3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid ethyl ester)calcium,

bis(3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid ethyl ester)nickel,

bis[3,3-bis(3-tert-4-hydroxyphenyl)butyric acid]glycol ester,

N,N'-bis[(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine,

2,2'-oxamidobis[ethyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate],

2,2'-methylenebis(4-methyl-6-tert-butylphenol) terephthalate,

1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene,

3,9-bis[1,1-dimethyl-2-{β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane,

2,2-bis[4-(2-(3,5-di-tert-butyl-4-hydroxyhydrocinnamoyloxy))ethoxyphenyl]propane,and

alkyl esters of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid.

Of the alkyl esters of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionicacid mentioned above, particularly preferred are alkyl esters havingalkyl group of not greater than 18 carbon atoms.

Furthermore, the following compounds are particularly preferably used inthe present invention:

tetrakis[methylene3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane,

bis(3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid ethyl ester)calcium,

bis(3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid ethyl ester)nickel,

bis[3,3-bis(4-hydroxy-3-tert-butylphenyl)butyric acid]glycol ester,

N,N'-bis[(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine,

2,2'-oxamidobis[ethyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate],

2,2'-methylenebis(4-methyl-6-tert-butylphenol) terephthalate,

1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene,

3,9-bis[1,1-dimethyl-2-{β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane,

1,3,5-tris[(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxyethyl]isocyanurate,and

2,2-bis[4-(2-(3,5-di-tert-butyl-4-hydroxyhydrocinnamoyloxy))ethoxyphenyl]propane.

These phenolic stabilizers are used singly or in combination.

Organic Phosphite Stabilizers (b)

Though conventionally known organic phosphite stabilizers are usedwithout specific restriction in the present invention, concrete examplesof the organic phosphite stabilizers include

trioctyl phosphite, trilauryl phosphite, tridecyl phosphite, octyldiphenyl phosphite, tris(2,4-di-tert-butylphenyl) phosphite, triphenylphosphite, tris(butoxyethyl) phosphite, tris(nonylphenyl) phosphite,distearylpentaerithrytol diphosphite,tetra(tridecyl)-1,1,3-tris(2-methyl-5-tert-butyl-4-hydroxyphenyl)butanediphosphite, tetra(C₁₂ -C₁₅ mixed alkyl)-4,4'-isopropylidenediphenyldiphosphite,tetra(tridecyl)-4,4'-butylidenebis(3-methyl-6-tert-butylphenol)diphosphite, tris(3,5-di-tert-butyl-4-hydroxyphenyl) phosphite,tris(mixed monononylphenyl, dinonylphenyl) phosphite,hydrogenated-4,4'-isopropylidenediphenol polyphosphite, bis(octylphenyl)bis[4,4'-butylidenebis(3-methyl-6-tert-butylphenol)] 1,6-hexanedioldiphosphite, phenyl 4,4'-isopropylidenediphenol pentaerythritoldiphosphite, tris[4,4'-isopropylidenebis(2-tert-butylphenol)] phosphite,phenyl diisodecyl phosphite, di(nonylphenyl) pentaerythritoldiphosphite, tris(1,3-distearoyloxyisopropyl) phosphite,4,4'-isopropylidenebis(2-tert-butylphenol) di(nonylphenyl) phosphite,and 9,10-dihydro-9-oxa-9-oxa-10-phosphaphenanthrene-10-oxide.

In addition, bis(dialkylphenyl) pentaerythritiol diphosphite estershaving the formula (1) of spiro type or the formula (2) of cage typeillustrated below are also used:

Usually, a mixture of both isomers is most often used due to utilizationof an economically advantageous process for manufacturing such phosphiteester. ##STR2## wherein R¹, R² and R³ are each a hydrogen or an alkylgroup having 1 to 9 carbon atoms, preferably a branched alkyl group,particularly preferably a tert-butyl group, the most preferablesubstitution positions of R¹, R² and R³ on the phenyl groups being 2-,4- and 6-positions. Preferable phosphite esters includebis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite andbis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, andthere may also be mentioned phosphonites having a structure wherein acarbon atom is directly bonded to a phosphorus atom, such astetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite.

These organic phosphite stabilizers are used singly or in combination.

Thioether Stabilizers (c)

Though conventionally known thioether stabilizers are used withoutspecific restriction in the present invention, concrete examples of thethioether stabilizers include

dialkyl esters such as dilauryl, dimyristyl and distearyl ester ofthiodipropionic acid, esters of alkylthiopropionic acid such as butyl-,octyl-, lauryl- and stearylthiopropionic acid with a polyhydric alcohol(for example, glycerine, trimethylolethane, trimethylolpropane,pentaerythritol and trishydroxyethyliscyanurate), such aspentaerythritoltetralaurylthiopropionate. More concretely, the thioetherstabilizers include dilauryl thiodipropionate, dimyristylthiodipropionate, lauryl stearyl thiodipropionate and distearylthiodibutyrate.

These thioether stabilizers are used singly or in combination.

Hindered Amine Stabilizers (d)

There are used without specific restriction as the hindered aminestabilizers conventionally known compounds having a structure whereinmethyl groups are substituted for all the hydrogen atoms bonded to thecarbon atoms at the 2-and 6-positions of piperidine. Concrete examplesof the hindered amine stabilizers include

(1) bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate,

(2) dimethylsuccinate-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidinepolycondensate,

(3)poly[[6-(1,1,3,3-tetramethylbutyl)imino-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)imino]],

(4) tetrakis(2,2,6,6-tetramethyl-4-piperidyl)1,2,3,4-butanetetracarboxylate,

(5) 2,2,6,6-tetramethyl-4-piperidyl benzoate

(6)bis(1,2,6,6-pentamethyl-4-piperidyl)-2-(3,5-di-tert-butyl-4-hydroxybenzyl)-2-n-butylmalonate,

(7) bis-(N-methyl-2,2,6,6-tetramethyl-4-piperidyl) sebacate,

(8) 1,1'-(1,2-ethanediyl)bis(3,3,5,5-tetramethylpiperazinone),

(9) (mixed 2,2,6,6-tetramethyl-4-piperidyl/tridecyl)1,2,3,4-butanetetracarboxylate,

(10) (mixed 1,2,2,6,6-pentamethyl-4-piperidyl/tridecyl)1,2,3,4-butanetetracarboxylate,

(11) mixed{2,2,6,6-tetramethyl-4-piperidyl/β,β,β',β'-tetramethyl-3,9-[2,4,8,10-tetraoxaspirio(5,5)undecane]diethyl}1,2,3,4-butanetetracarboxylate,

(12) mixed{1,2,2,6,6-pentamethyl-4-piperidyl/β,β,β',β'-tetramethyl-3,9-[2,4,8,10-tetraoxaspiro(5,5)undecane]diethyl}1,2,3,4-butanetetracarboxylate,

(13)N,N'-bis(3-aminopropyl)ethylenediamine-2,4-bis[N-butyl-N-(1,2,2,6,6-pentamethyl-4-piperidyl)amino]-6-chloro-1,3,5-triazinecondensate,

(14)poly[[6-N-morpholinyl-1,3,5-triazine-2,4-diyl]-[(2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)imino]],

(15) condensate ofN,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine with1,2-dibromoethane, and

(16)[N-(2,2,6,6-tetramethyl-4-piperidyl)-2-methyl-2-(2,2,6,6-tetramethyl-4-piperidyl)imino]propionamide.

Of the hindered amine stabilizers, those especially preferably employedare the compounds denoted by (1), (2), (3), (4), (8), (10), (11), (14)and (15).

These hindered amine stabilizers are used singly or in combination.

Metal Salts of Higher Aliphatic Acid (e)

Examples of methal salts of the higher aliphatic acid which may be usedin the invention include alkaline earth metal salts such as magnesiumsalts, calcium salts and barium salts, alkali metal salts such as sodiumsalts, potassium salts and lithium salts, cadmium salts, zinc salts andlead salts of higher aliphatic acids such as stearic acid, oleic acid,lauric acid, capric acid, ariachidic acid, palmitic acid, behenic acid,12-hydroxystearic acid, ricinolic acid, and montanic acid. Concreteexamples of the higher aliphatic acid metal salts include

magnesium stearate, magnesium laurate, magnesium palmitate, calciumstearate, calcium oleate, calcium laurate, barium stearate, bariumoleate, barium laurate, barium arachidate, barium behenate, zincstearate, zinc oleate, zinc laurate, lithium stearate, sodium stearate,sodium palmitate, sodium laurate, potassium stearate, potassium laurate,calcium 12-hydroxystearate and calcium montanate and zinc montanate.

These higher aliphatic acid metal salts are used singly or incombination.

Higher aliphatic acid metal salts as described above act as a lubricantand a rust-preventive agent. Ethylene/pentene-1 compolymer compositionscontaining such higher aliphatic acid metal salts therefore areexcellent in moldability and effective in rust prevention of moldingmachines, etc.

Furthermore, when a higher aliphatic acid metal salt as described abovein an amount as described below is added to an ethylene/pentene-1copolymer or an ethylene/pentene-1 copolymer composition, the metal saltis capable of sufficiently absorbing residual chlorine originating fromthe catalyst for the above-mentioned copolymer. Accordingly, resinobtained from the copolymer or the copolymer composition does not showdeterioration of its characteristics.

Preferable examples of the compositions according to the presentinvention include

(1) a composition comprising

an ethylene/pentene-1 copolymer in an amount of 100 parts by weight, and

a phenolic stabilizer (a) in the amount of 0.005 to 5 parts by weight,preferably 0.005 to 2 parts by weight, more preferably 0.01 to 1 part byweight;

(2) a composition comprising

an ethylene/pentene-1 copolymer in an amount of 100 parts by weight,

a phenolic stabilizer (a) in an amount of 0.005 to 5 parts by weight,preferably 0.005 to 2 parts by weight, more preferably 0.01 to 1 part byweight, and at least one compound selected from the group consisting of

(b) organic phosphite stabilizers,

(c) thioether stabilizers,

(d) hindered amine stabilizers and

(e) higher aliphatic acid metal salts

in an amount of 0.005 to 5 parts by weight, preferably 0.005 to 2 partsby weight, more preferably 0.01 to 1 part by weight;

(3) a composition comprising

an ethylene/pentene-1 copolymer in an amount of 100 parts by weight, and

an organic phosphite stabilizer (b) in an amount of 0.005 to 5 parts byweight, preferably 0.005 to 2 parts by weight, more preferably 0.01 to 1part by weight;

(4) a composition comprising

an ethylene/pentene-1 copolymer in an amount of 100 parts by weight,

an organic phosphite stabilizer (b) in an amount of 0.005 to 5 parts byweight, preferably 0.005 to 2 parts by weight, more preferably 0.01 to 1part by weight, and

at least one compound selected from the group consisting of

(c) thioether stabilizers,

(d) hindered amine stabilizers and

(e) higher aliphatic acid metal salts

in an amount of 0.005 to 5 parts by weight, preferably 0.005 to 2 partsby weight, more preferably 0.01 to 1 part by weight;

(5) a composition comprising

an ethylene/pentene-1 copolymer in an amount of 100 parts by weight, and

a thioether stabilizer (c) in an amount of 0.005 to 5 parts by weight,preferably 0.005 to 2 parts by weight, more preferably 0.01 to 1 part byweight;

(6) a composition comprising

an ethylene/pentene-1 copolymer in an amount of 100 parts by weight,

a thioether stabilizer (c) in an amount of 0.005 to 5 parts by weight,preferably 0.005 to 2 parts by weight, more preferably 0.01 to 1 part byweight, and

at least one compound selected from the group consisting of

(d) hindered amine stabilizers and

(e) higher aliphatic acid metal salts

in an amount of 0.005 to 5 parts by weight, preferably 0.005 to 2 partsby weight, more preferably 0.01 to 1 part by weight;

(7) a composition comprising

an ethylene/pentene-1 copolymer in an amount of 100 parts by weight, and

a hindered amine stabilizer (d) in an amount of 0.005 to 5 parts byweight, preferably 0.005 to 2 parts by weight, more preferably 0.01 to 1part by weight;

(8) a composition comprising

an ethylene/pentene-1 copolymer in an amount of 100 parts by weight,

a hindered amine stabilizer (d) in an amount of 0.005 to 5 parts byweight, preferably 0.005 to 2 parts by weight, more preferably 0.01 to 1part by weight, and a higher aliphatic acid metal salt (e) in an amountof 0.005 to 5 parts by weight, preferably 0.005 to 2 parts by weight,more preferably 0.01 to 1 part by weight; and

(9) a composition comprising

an ethylene/pentene-1 copolymer in an amount of 100 parts by weight, and

a higher aliphatic acid metal salt (e) in an amount of 0.005 to 5 partsby weight, preferably 0.005 to 2 parts by weight, more preferably 0.01to 1 part by weight.

When these stabilizers are added in the amount range as described aboveto 100 parts by weight of the ethylene/pentene-1 copolymer, theresultant compositions of the invention show highly improved thermalresistance at low cost of the stabilizers without deteriorating theresin properties such as tensile strength.

The ethylene/pentene-1 copolymer compositions according to the presentinvention may be incorporated with such compounding agents usually addedto and mixed with polyolefins as diluents, heat-resistant stabilizers,weather-resistant stabilizers, pigments, dyes, lubricants and antistaticagents in addition to the above-described components so long as theincorporation does not impair the object of the invention.

EFFECT OF THE INVENTION

The ethylene/pentene-1 copolymers of the present invention fulfillaforementioned specific requisites, so that when the copolymer is moldedinto a film, the obtained film has a good balance between impactresistance and tear properties. Further, the film formed from thecopolymer shows high SC resistance and has haze development of extremelylow level. Accordingly, the ethylene/pentene-1 copolymer of theinvention can be favorably applied to various uses.

In the processes for the preparation of an ethylene/pentene-1 copolymeraccording to the invention, the polymerization reaction is performedunder the aforementioned specific conditions. Therefore, when acopolymer prepared by the processes is molded into a film, the obtainedfilm has a good balance between impact resistance and tear properties.Further, the film shows high SC resistance and has haze development ofextremely low level. Accordingly, the ethylene/pentene-1 copolymerprepared by the processes of the invention can be favorably applied tovarious uses.

The ethylene/pentene-1 copolymer composition of the invention isexcellent in heat stability in the molding stage, long-term heatstability and weatherability. Further, the ethylene/pentene-1 copolymercomposition hardly suffers heat deterioration when the composition isformed into a molded product such as a film, so that the composition ofthe invention can be employed for forming a molded product having highimpact strength and good tear properties.

EXAMPLE

The present invention is further described by the following Examples,but the Examples are by no means given to restrict the invention.

The stabilizers used in the Examples are listed as follows, andestimation of the stabilities of films are measured by the followingmethods.

USED STABILIZERS Phenolic Stabilizers

A: Stearyl ester of β-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionicacid. (trade name; Irganox 1076, from Nippon Ciba Geigy, Co.)

B:Tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane(trade name; Irganox 1010, from Nippon Ciba Geigy, Co.)

Organic Phosphite Stabilizers

C: Tris (2,4-di-tert-butylphenyl) phosphite (trade name; Phosphite 168,from Nippon Ciba Geigy, Co.)

D: Tetrakis (2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite(trade name; Sandostab P-EPQ, from Sandoz, Co.)

Thioether Stabilizers

E: Dilauryl thiodipropionate (trade name; Antiox L, from Nippon Yusi,Co.)

F: Distearyl thiodipropionate (trade name; DSTP"Yoshitomi", fromYoshitomi Pharmacy, Co.)

G: Pentaerythritol tetra β-mercapto laurylthiopropionate (trade name:Seenox 412S, from Shipro Chemical, Co.)

Hindered Amine Stabilizers

H: Bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate (trade name: SanolLS770, from Sankyo, Co.)

I:Poly[[6-(1,1,3,3-tetramethylbutyl)imino-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)imino]] (trade name; Chimassorb 944LD,from Nippon Ciba Geigy, Co.)

Metal Salts of Higher Aliphatic Acid

J: Calcium stearate

K: Calcium 12-hydroxystearate

L: Magnesium Stearate

M: Calcium montanate

Measurement Method

MFR: An MFR is measured in accordance with ASTM D 1238 under 2.16 kgload at 190° C.

Impact Strength: An impact strength is measured in accordance with JISP8134, which states in pertinent part:

JAPANESE INDUSTRIAL STANDARD J I S Testing Method for Puncture ofPaperboard P 8134-1986 (Reaffirmed: 1984)

1. Scope

This Japanese Industrial Standard specifies the testing method (¹) forpuncture of paperboard and corrugated board.

Remark: In this standard, the particulars in {} are in accordance withthe International System of Units (SI) and given for reference only.

2. Apparatus

The testing apparatus shall be provided with the following components.

(1) Pendulum which has a 90° arc-shaped arm to which the piercing partcan be attached and can be swung freely

(2) Piercing part which is a right-angle trigonal pyramid of 25.4 mm inheight which has a luster of mirror surface, can be firmly attached tothe end of the arc-shaped arm and has edges which are curved with theradius of curvature of 1.5 mm

(3) Metallic collar which is constructed to slightly deflect so that thearm of the pendulum is protected from friction due to spring-returningof the test piece after the piercing part perforates the test piece.

(4) Device capable of horizontally supporting the pendulum and releasingit.

(5) Test piece clamp plate which properly clamps the test piece at thehorizontal position.

(6) Pointer and dial which indicate the maximum arc movement of thependulum after the test piece is perforated by the piercing part.

(7) Auxiliary weight and fixture to be attached to the pendulum which iscapable of measuring the amount of work necessary for perforation up toat least 400 kgf·cm{39.2 J}.

(8) Inserting plate which has an opening of equilateral triangle ofwhich one side is 106 mm in length and the vertex is curved with the 3mm radius and can be inserted between the clamp plates to fix the testedpart and removed for adjusting the machine

3. Adjustment

The testing apparatus shall be placed horizontally and adjusted asdescribed below.

(1) Zero adjustment of the scales shall be conducted by removing theinserting plate, setting the tip of the pointer to a position approx. 25mm higher than the zero line on the scale and swinging the pendulum. Inthis case, the metallic collar shall be left as is attached. Repeat theoperation several times to ascertain that the pendulum causes thepointer to swing to the zero point.

When the pointer does not accurately indicate at the zero point, adjustthe adjust screw for the pointer.

(2) Check the pointer for friction as follows. In other words, set thepoint to the highest position of the scale before the pendulum isreleased and check whether the tip of the pointer comes to within 3 mmfrom the zero line after the pendulum is released.

(3) When the reading is 3 mm or over, the pointer has excessive frictionand therefore the shaft of the pointer should be lubricated or thefriction spring should be loosened.

(4) The testing apparatus shall be corrected referring to 4. in JIS P8116.

4. Test Piece

The test piece shall be 150 mm² or over in dimensions and clamped sothat the test piece does not slip between the clamp plates. Theperforating position shall be at least 40 mm away from a part considereddetrimental to the test. The test piece shall be adjusted to comply withthe requirements specified in JIS P 8111 before the test.

5. Procedure

(1) The test shall be conducted in the atmosphere conforming to therequirements specified in JIS P 8111.

(2) Hold the test piece correctly between the clamp plates, mount themetallic collar onto the base of the piercing part, set the pointer to aposition where the tip of the pointer is approx. 25 mm higher than areading position expected in the test and release the pendulum. Read thepointer after the pendulum is stopped. The scale as much as 25% of thescale angle from the maximum scale point should not be used.

(3) The test shall be conducted so that one edge of the trigonal pyramidof the piercing part is positioned in the longitudinal direction of thetest piece in case of the paperboard and in the corrugating direction incase of the corrugated board and the test shall further be conducted inthe direction at right angles to the above directions.

(4) The test shall be conducted at least five times in each direction.

6. Report

The valves obtained from the test piece with respect to each directionshall be expressed by three significant digits in kgf.cm {J} inaccordance with JIS Z 8401 and reported as follows:

(1) Overall mean value

(2) Mean value, maximum value and minimum value with respect to eachdirection

(3) Number of times of tests for each direction.

The content of constitution unit derived from pentene-1

1) Teflon tape is laminated on 0.2 g of ethylene/pentene-1 copolymer. Ahot plate is then placed on the laminate and is then transferred to ahot press adjusted to 180°±2° C. to form a film having a thickness of100 μ to 200 μ.

The thus obtained film is subjected to infrared spectral analysis at awave length between 1420 cm⁻¹ and 1300 cm⁻¹ using A-302 type infrared(IR) spectrophotometer (manufactured by Nippon Bunko K. K., Japan).Absorbance(D) per unit thickness (μ) assigned to methyl symmetricangular vibration at 1378 cm⁻¹ is measured. The branch number derivedfrom pentene-1 is calculated from an analytical curve.

The branch number (N/1000 carbon atoms) is determined by the followingformula(1):

    N=7.77×(D)-3.73                                      (1).

The content of pentene-1(mol %) is calculated from the branch number(N/1000 carbon atoms) by the following formula(2):

    Comonomer(mol %)=200×N/(1000-3N)                     (2).

The analytical curve is prepared by using a standard sample determinedfrom the amount of comonomer by ¹³ C-NMR analysis as described below.

(2) (i) Preparation of test sample: 0.35 g of ethylene/pentene-1copolymer is added to 2 ml of hexachlorobutadiene and dissolved byheating. To the resultant solution is added 0.5 ml of deuterium benzeneand then charged to a nuclear magnetic resonance (NMR) tube having aninner diameter of 10 mm, thereby preparing a test sample.

(ii) Measurement: The thus prepared test sample is subjected to ¹³ C-NMRanalysis at 120° C. using FX-100 type NMR measurement apparatus(manufactured by NIHON DENSHI K.K., Japan). The number of integrating is20,000 or more.

The content of constitution unit derived from pentene-1 (mol fraction)is defined by the following formula according to the methods of Bovey,et al. (Academic Press 80, 1972) and Ray, et al. (Macromolecules, 10,773, 1977). ##EQU1## wherein Iαα is a peak strength at 38.98 ppm,

Iαγ is a peak strength at 34.72 ppm,

Iαδ is a peak strength at 34.47 ppm,

Iβδ is a peak strength at 27.52 ppm,

Iγβ is a peak strength at 30.21 ppm,

Iδδ is a peak strength at 29.96 ppm.

The content of constitution units derived from comonomers in theExamples and Comparative Examples are determined.

ESTIMATION OF STABILITY

(1) Thermal stability in the molding stage

MFR of films: The film shows better thermal stability when thedifference between the MFR of the pellets and that of the film issmaller.

Physical properties of films (Impact Strength): The film shows lessdeterioration in the molding stage when the film has a larger value ofimpact strength.

(2) Long-term heat stability

A film is aged at 100° C. in a gear oven, and a period of time from thestart of aging to the time when the tensile elongation becomes 1/2 ofthat of the initial value is measured.

The film has better heat-resistant and aging-resistant properties whenit shows a longer period of time.

(3) Weatherability

A film is irradiated with light for 500 hours by using a sunshineweatherometer at a discharge voltage of 50 V and a discharge current of60 A, and with rain, and a retention of tensile elongation thereof ismeasured.

The film has better weatherability when it shows a larger retention oftensile elongation.

EXAMPLE 1 Preparation of titanium catalyst

A mixture of 714 g of anhydrous magnesium chloride, 3.7 l of decane and3.5 l of 2-ethylhexyl alcohol was heated at 130° C. for 2 hours toprepare a homogeneous solution. To this solution was added 290 g ofethyl benzoate, and the mixture was stirred at 130° C. for 1 hour. Thehomogeneous solution thus obtained was cooled to room temperature, andthe whole solution was added dropwise to 20 l of titanium tetrachloridekept at -20° C. over a period of 1 hour. After completion of theaddition, the temperature of the mixture was elevated to 80° C. over aperiod of 2 hours, and the mixture was held with stirring at thattemperature for 2 hours. After completion of the 2-hour reaction, theresulting solid was collected by hot filtration and suspended in 28 l ofTiCl₄, followed by reaction at 90° C. for 2 hours. After completion ofthe reaction, the solid was collected by hot filtration, and wasthoroughly washed with decane kept at 90° C. and hexane kept at roomtemperature until no free titanium compound was detected in the washingliquid to obtain a titanium catalyst component. The titanium catalystcomponent contained 4.8% by weight of titanium, 52% by weight ofchlorine, 16% by weight of magnesium and 6.2% by weight of ethylbenzoate.

Pre-polymerization

Into a 20-liter reactor equipped with a stirrer, were introduced 10liter of hexane, 300 mmoles of triethylaluminum and 100 mmoles in termsof titanium atom of the titanium catalyst component obtained above in anatmosphere of nitrogen. Into the mixture in the reactor was fedpropylene at a rate of 100 g/hr for 3 hours. During that operation, thetemperature in the reactor was kept at 20° C. After three hours from theinitiation of feeding the propylene, the propylene supply was stopped,and nitrogen was fed into the reactor to purge with nitrogen. Stirringthe reaction mixture was stopped, and the mixture was allowed to stand,followed by removal of the supernatant. The solid left was washed threetimes with purified hexane.

Polymerization

To a polymerizer having a diameter of 40 cm Φ and a capacity of 400 l asshown in FIG. 3 were fed continuously through a pipe 1 theabove-mentioned pre-polymerized catalyst at a rate of 0.5 mmol/h interms of Ti atom and triisobutylaluminum at a rate of 25 mmol/h.Simultaneously, into the polymerizer were fed through a pipe 2 ethyleneat a rate of 9.4 kg/h and 1-pentene at a rate of 3.1 kg/h, and through apipe 3 hydrogen in such a proportion that the H₂ /ethylene molar ratioin the polymerizer is maintained at 0.10.

The polymerization conditions employed were such that the pressure is 18kg/cm² G, the polymerization temperature is 80° C., the residence timeis 4 hours, and the linear velocity of the circulating gas in the vaporphase polymerizer is maintained at a rate of 45 cm/sec. The circulatinggas from a pipe 4 passed through a condenser B and circulated in thepolymerizer through a fan C.

The resulting copolymer was discharged at a rate of 4.7 kg/hr out of thesystem through a pipe 5. The thus obtained copolymer had a density of0.924 g/cm³ and MFR of 1.1 g/10 min.

Preparation of composition

To the copolymer obtained above were added Irganox 1076, a product ofCiba-Geigy (0.20% by weight), calcium stearate (0.10% by weight) andsilica (0.10% by weight), and the resulting mixture was granulated.

Molding of film

Using a commercially available T-die film forming machine equipped withan extruder having diameter of 65 mm, the copolymers was molded into asheet of 420 mm in width and 0.04 mm in thickness.

The molding was carried out in such condition that the resin temperaturewas 235° C., the revolution of a screw of the extruder was 40 rpm, thechill roll temperature was 35° C., the film forming speed was 20 m/min,and a draft ratio was 0.057.

Physical properties of the films obtained were as shown in Table 2.

EXAMPLE 2 AND COMPARATIVE EXAMPLES 1 AND 2

The copolymerization of Example 1 was repeated except that modifiedconditions as shown in Table 1 were employed to obtain copolymersrespectively shown in Table 2.

In Table 2, the impact strength was determined in accordance with JISP8134, as previously described, and the tear strength was determined inaccordance with JIS Z-1702, which states in pertinent part:

JAPANESE INDUSTRIAL STANDARD J I S Polyethylene Films for Packaging Z1702-1986

1. Scope

This Japanese Industrial Standard specifies the polyethylene films,hereinafter referred to as the "films", for packaging.

Remark: The units and numerical values given in { } in this standard arein accordance with the conventional units, and are the values specifiedas this standard.

2. Classes

The films shall be classified into 4 classes as shown in Table 1according to the properties and quality.

                  TABLE 1                                                         ______________________________________                                        Class     Characteristics                                                     ______________________________________                                        Class 1 A Comparatively flexible                                              Class 1 B Comparatively flexible, especially resistant                                  to shock                                                            Class 2 A Comparatively rigid                                                 Class 2 B Comparatively rigid, for ultra-thin film or                                   for reinforcement purpose                                           ______________________________________                                    

3. Quality

The film shall be homogeneous and free from harmful defects in use suchas bubbles, uneveness, wrinkle, fish eye, mixture of foreign substances,pin holes and the like, and meet the specifications as shown in Table 2,when tested in accordance with 7.

                                      TABLE 2                                     __________________________________________________________________________            Quality                 Applicable                                    Test item                                                                             Class 1 A                                                                           Class 1 B                                                                           Class 2 A                                                                           Class 2 B                                                                           item                                          __________________________________________________________________________    Tensile strength                                                                      11.8 {120}                                                                          16.7 {170}                                                                          19.6 {200}                                                                          29.4 {300}                                                                          7.5                                           MPa {kgf/cm.sup.2 }                                                                   min.  min.  min.  min.                                                Elongation %                                                                          150 min.                                                                            250 min.                                                                            150 min.                                                                            150(.sup.1) min.                                                                    7.5                                           Impact test                                                                            --   To meet                                                                              --   To meet                                                                             7.6                                                         the re-     the re-                                                           quirements  quirements                                          __________________________________________________________________________     Note (.sup.1)Elongation shall be not less than 50% for nominal thickness      of 0.010 mm, and not less than 100% for nominal thickness of 0.015 mm.   

4. Shape

The section of film perpendicular to the direction of forming work shallbe a tubular or a filmy shape.

5. Dimensions

5.1 Thickness The nominal thickness of films shall be as specified inTable 3, and the film thickness, ratio of the difference between thenominal and average thickness to the nominal thickness, and thedifference of the thickness from the nominal thickness shall conform tothe requirements of Table 3, when tested in accordance with 7.3.

                  TABLE 3                                                         ______________________________________                                                                  Unit: mm                                                      Tolerance of the ratio                                                                       Permissible range                                    Nominal   of difference of                                                                             of the difference                                    thickness average thickness                                                                            of thickness                                         t.sub.0   Δt (%)   Δt                                             ______________________________________                                        0.010     +15            +0.004                                                         -10            -0.003                                               0.015                    +0.005                                                                        -0.004                                               0.020      ±9         ±0.006                                            0.025                    ±0.006                                            0.030                    ±0.007                                            0.035                    ±0.007                                            0.040                    ±0.008                                            0.045                    ±0.008                                            0.050      ±7         ±0.009                                            0.060                    ±0.010                                            0.070                    ±0.011                                            0.080                    ±0.012                                            0.090                    ±0.013                                            0.100                    ±0.013                                            ______________________________________                                         Remark: For the films of nominal thickness of 0.010 mm and 0.015 mm, this     table shall be applied only to Class 2 B.                                

5.2 Lay-Flat Width or Width and Length The lay-flat width(²) or widthand length shall be as specified in Table 4 and their tolerances shallconform to the requirements of Table 5 when tested in accordance with7.4.

                  TABLE 4                                                         ______________________________________                                        Lay-flat width or width mm                                                    Range of nominal                                                                            Interval of nominal                                             dimension     dimension      Length m                                         ______________________________________                                        70 to 500     10             As agreed                                        500 to 1000   20 and 50      between the                                      1000 min.     50             parties                                                                       concerned                                        ______________________________________                                    

                  TABLE 5                                                         ______________________________________                                                                  Unit: mm                                            Lay-flat width                                                                             Tolerances on lay-                                                                           Tolerances on                                     or width     flat width or width                                                                          length                                            ______________________________________                                        70 to 100    ±2          Minus side                                        110 to 200   ±3          is not                                            210 to 300   ±4          allowed.                                          310 to 400   ±5                                                            410 to 500   ±6                                                            520 to 800   ±7                                                            820 to 1000  ±10                                                           1050 min.    ±1.2(%)                                                       ______________________________________                                    

6. Material and Manufacturing Method

The film shall be formed in film by the inflation or T-die method using,as the primary constituent, the material specified in JIS K 6748 or JISK 6731.

7. Test Methods

7.1 Sampling Method Cut off lengthwise three samples with a length ofnot less than 1 m (sufficient quantity to take each test piece) from thetest film.

Remark: Length and Width of Film Regarding the length and width, thedirection parallel to the flow of forming work is referred to as thevertical direction and the direction perpendicular to that flow isreferred to as the horizontal direction.

7.2 Pre-Treatment of Sample and Test Conditions The test conditions offilm and the pre-treatment conditions of the sample or the test pieceshall be, in principle, the standard temperature condition Grade 2(23°±2° C.) specified in JIS K 7100. The pre-treatment period shall benot less than 1 h.

7.3 Measuring Method for Thickness

(1) Thickness Gauge A thickness gauge as specified in JIS B 7509, inwhich the gauge head of spindle has a smooth flat plane of 5°±0.01 mm indiameter and the anvil has a smooth flat surface of not less than 30 mmin diameter being arranged perpendicular to the spindle, shall be used.The dial shall be not less than 50 mm in diameter and shall have a scalecapable of reading to 0.001 mm. In this case, a thickness gauge having apressing load of 1226±147 mN {125±15 gf} shall be used.

(2) Procedure Measure the thickness at 8 points distributed at almostequal intervals along a cut side of one of the samples cut off inaccordance with 7.1. The measuring points shall be at least 5 mm insidefrom the cut side.

(3) Calculation Obtain the maximum, minimum and average thickness fromwhole measurements, and calculate the thickness difference from nominalthickness and the ratio of difference of average thickness from nominalthickness according to the following formula: ##EQU2## where t_(max) :maximum thickness (measured value) (mm)

t_(min) : minimum thickness (measured value) (mm)

t₀ : nominal thickness (mm)

Δt: thickness difference from nominal thickness (mm)

t average thickness (mm) (average of measured values)

t⁺ -t₀ : difference of average thickness (mm) (difference betweenaverage and nominal values)

Δt⁺ : ratio of the difference of average thickness to nominal thickness(%)

7.4 Measuring Method for Lay-Flat Width or Width

(1) Measuring Instrument The measuring instrument specified in JIS B7516 or JIS B 7512 or that equal or superior in accuracy thereto shallbe used.

(2) Procedure Measure at 3 points at almost equal intervals along thelongitudinal direction of film of 3 samples cut in off accordance with7.1, and obtain the average value.

7.5 Tensile Strength Test The tensile strength test shall be carried outas follows:

(1) Testing Machine A tensile testing machine of a constant crossheadspeed type or pendulum type shall be used. The testing machine shall beprovided with an indicating device and a gripping device for test piece,and its load indicating accuracy shall be within ±2%. The breaking loadshould be in a range of 15 to 85% of the machine capacity.

(2) Test Piece The test piece shall be of a strip form having a width of15±0.1 mm, with its parallelism being within 0.1 mm, and a length enoughlong for carrying out the measurement (about 180 mm) or of a dumbellform

The number of test pieces shall be each not less than 5 for longitudinaland transversal directions of a sample.

(3) Procedure Mark 2 marked lines for elongation measurement on thesurface of the test piece with ink or crayon having no harmful effect onthe specimen. The distance between the marked lines shall be 50±2 mm fora strip type and 40±2 mm for a dumbell type.

The measurement of the thickness of test piece shall be made at 3 pointsbetween the marked lines of each test piece and take the smallest valueas the thickness.

The test piece shall be attached to a testing machine so as the distancebetween upper and lower grips is about 100 mm for a strip type testpiece and 80±5 mm for dumbbell type test piece, and the centre of testpiece coincides with the center of distance between grips.

The test speed shall be 500 mm±10% per minute, apply tensile load tillthe test piece breaks and obtain the maximum load during the test andthe gauge length at breakage. If a slip is observed in the test pieceduring the test, however, the result shall be discarded, and in the casebreakage occurred outside the marked line, the results shall also bediscarded.

(4) Calculation The value of the maximum load till breakage divided bythe initial sectional area shall be the tensile strength in MPa {kgf/cm²} and each average value for longitudinal and lateral directions shallbe obtained to 3 significant figures.

The elongation shall be calculated from the following formula and eachaverage value for longitudinal and lateral directions be obtained to 2significant figures. The specified values for tensile strength andelongation in Table 2 shall be the average values in the direction inwhich the values are lower than those of the other. ##EQU3## where l:elongation (%)

L: gauge length at breakage (mm)

L₀ : gauge length before test (mm)

7.6 Impact Test The impact test shall be as shown below:

(1) Testing Apparatus The testing apparatus shall comprise a test pieceholder, dart detacher, dart, weight, etc.

(a) The test-piece holder shall be of such structure that it is able tofix the test piece horizontally, has a circular portion of 125±2 mm ininner diameter, and is able to accept the impact due to the fall ofdart. A test piece holder which is able to pneumatically fix the testpiece is desirable.

(b) The dart detacher shall be so constructed that it holds the dart ata specified height from the test piece and is able to let fall the darton the middle part of test piece.

(c) The dart shall have a shaft of 6.4 mm in diameter and not less than115 mm in length to which a semi-spherical weight (added weight) ofaluminium or phenol resin having a diameter of 38±1 mm can be attached,and its mass shall be about 30 g.

(d) The weight shall be added to the dart so as to obtain a test mass(³)given in Table 6 with an accuracy of ±0.5%. It is composed of astainless steel or brass cylinder of 30 mm in diameter with a hole of6.5 mm in diameter at the centre, and is able to be adjusted in itsthickness to attain the specified test mass.

(2) Test Piece

(a) The test piece shall be not less than 150 mm in length and width ornot less than 150 mm in diameter.

(b) The test piece shall be free from pinholes, wrinkles, folds, andother obvious defects.

(c) The number of test pieces shall be 10.

(3) Procedure After having confirmed that the dart will fall at themiddle of the test piece, attach the test piece to the test pieceholder. Attach the dart to the dart detacher, adjust the height of thetip of dart from the test piece surface to 660±4 mm, and hold. Then,carry out the test on 10 test pieces with the test mass specified inTable 6, and ascertain that not less than half the test pieces remainwithout breaking. In this test, care shall be taken so that the dartdoes not give impact twice to the test piece.

                  TABLE 6                                                         ______________________________________                                        Nominal                                                                       thickness      Test mass g                                                    mm             Class 1 B                                                                              Class 2 B                                             ______________________________________                                        0.010          --        60                                                   0.015          --        70                                                   0.020          50        90                                                   0.025          60       100                                                   0.030          70       120                                                   0.035          80       130                                                   0.040          90       150                                                   0.045          95       160                                                   0.050          100      180                                                   0.060          120      210                                                   0.070          140      240                                                   0.080          160      270                                                   0.090          180      300                                                   0.100          200      330                                                   ______________________________________                                    

8. Inspection

The inspection of the film shall be carried out according to the testspecified in 7. and shall conform to 3. and 5.

8.1 The inspection items shall be appearance, dimensions, tensilestrength, elongation, and impact test.

8.2 The inspection shall be carried out according to an inspectionmethod designed reasonably.

9. Marking

The film shall be packaged so as not to be injured, and be marked withfollowing information on a conspicuous place of each package.

(1) Name

(2) Class

(3) Dimension

(4) Year and month of manufacture or its abbreviation

(5) Name of manufacturer or its abbreviation

                  TABLE 1                                                         ______________________________________                                                         Amount of                                                                     comonomer fed                                                                             H.sub.2 /ethylene                                       Comonomer (kg/h)      molar ratio                                      ______________________________________                                        Example 2                                                                              1-Pentene   3.5         0.15                                         Comparative                                                                            1-Butene    4.3         0.18                                         Example 1                                                                     Comparative                                                                            1-Hexene    3.1         0.19                                         Example 2                                                                     ______________________________________                                    

                                      TABLE 2                                     __________________________________________________________________________                                        Content                                                           Impact                                                                             Tear   of                                                                strength                                                                           strength                                                                             Comonomer                                              MFR   Density                                                                            of film                                                                            MD/TD  unit                                      Run   Comonomer                                                                            (g/10 min)                                                                          (g/cm.sup.3)                                                                       (kg/cm)                                                                            (kg/cm)                                                                            RS                                                                              Wt % (mol %)                              __________________________________________________________________________    Example 1                                                                           1-Pentene                                                                            1.1   0.923                                                                              2300 55/140                                                                             42                                                                              8(3.4)                                    Example 2                                                                           1-Pentene                                                                            1.1   0.916                                                                              4500 65/150                                                                             69                                                                              12(5.2)                                   Compara-                                                                            1-Butene                                                                             1.1   0.923                                                                               700 30/90                                                                              23                                                                              8(4.2)                                    tive                                                                          Example 1                                                                     Compara-                                                                            1-Hexene                                                                             1.0   0.924                                                                              2300 80/210                                                                             29                                                                              7(2.5)                                    tive                                                                          Example 2                                                                     __________________________________________________________________________

EXAMPLE 3

A mixture of 119 g of a commercially available anhydrous magnesiumchloride, 579 ml of 2-ethylhexyl alcohol and 5.6 l of decane was heatedat 140° C. for 3 hours to prepare a homogeneous solution containingmagnesium chloride.

To this solution was added 70 ml of propionic acid, and the solution washeated at 70° C. for 1 hour, followed by cooling. To this solution wasadded dropwise with stirring at 20° C. a mixture of 178 ml oftriethylaluminum and 1.1 l of decane over a period of 30 minutes, andthe temperature was then elevated to 80° C. over a period of 1 hour,followed by maintaining the mixture at 80° C. for 1 hour to carry thereaction. To the mixture was then added dropwise a mixture of 89 ml oftriethylaluminum and 560 ml of decane over a period of 30 minutes,followed by heating at that temperature for 30 minutes. Thereafter, tothe mixture was added dropwise a mixture of 189 ml of diethylaluminumchloride and 1.3 l of decane over a period of 30 minutes, followed byheating at 80° C. for 1 hour.

Subsequently, the resulting solid was removed by filtration to prepare asolid component.

To a suspension of the thus obtain solid component in 5 l of decane wasadded 188 mmoles of 2-ethylhexoxytitanium trichloride and the mixturewas heated at 80° C. for 1 hour. The solid component was then separatedand washed with decane to prepare a solid titanium catalyst component.Separately, a portion collected from the slurry obtained by heating at80° C. for 1 hour, of which the decane had been removed and thenreplaced with hexane was then dried to obtain a dried catalystcomponent. It was confirmed on analysis of the dried catalyst component,that the solid titanium catalyst component obtained above contained 1.3%by weight of titanium, 12% by weight of magnesium and 36% by weight ofchlorine.

Pre-polymerization

A 200-liter nitrogen purged reactor equipped with a stirrer was chargedwith 100l of hexane, 1.5 moles of triethylaluminum and 0.5 mole in termsof titanium atom of the solid titanium catalyst component obtainedabove. To the mixture in the reactor was fed ethylene gas at a rate of 5kg/hr for four hours. During this operation, the system of the reactorwas maintained at 30° C. After four hours from the initiation of feedingethylene gas, the ethylene gas feeding was stopped, and nitrogen was fedto the reactor to purge the ethylene gas therefrom. After the stirrerwas stopped and the mixture was allowed to stand, the supernatant ofsaid mixture was removed therefrom, and the solid left was washed threetimes with purified hexane.

Polymerization

To a polymerizer having a diameter of 40 cm Φ and a capacity of 400 l asshown in FIG. 3 were fed continuously through a pipe 1 a suspension ofthe pre-polymerized catalyst component obtained above at a rate of 0.17mmol/h in terms of Ti atom and triisobutyaluminum at a rate of 2.5mmol/h and simultaneously were fed through a pipe 2 ethylene at a rateof 9.5 kg/h and 1-pentene at a rate of 2.9 kg/h and through a pipe 3 wasfed hydrogen in such an amount that H₂ /ethylene molar ratio in thepolymerizer become 0.10.

The polymerization conditions employed were such that the pressure is 18kg/cm² G, the polymerization temperature is 80° C., the residence timeis 4 hours, and the linear velocity of the circulating gas in the vaporphase polymerizer is maintained at a rate of 45 cm/sec. The circulatinggas from a pipe 4 passed through a condenser B and circulated to thepolymerizer through a fan C.

The resulting copolymer was discharged through a pipe 5 outside thesystem at a rate of 4.7 kg/Hr. The thus obtained copolymer had a densityof 0.923 g/cm³ and MFR of 1.1 g/10 min.

Preparation of composition

The composition was prepared from the copolymer obtained above in thesame procedure as in Example 1.

Molding of film

The film was prepared from the copolymer obtained above in the sameprocedure as in Example 1.

Physical properties of the film obtained are shown in Table 4.

EXAMPLE 4 AND COMPARATIVE EXAMPLES 3 AND 4

The copolymerization of Example 3 was repeated but employing modifiedconditions as shown in Table 3 to obtain copolymers respectively shownin Table 4.

Physical properties of the films obtained from the copolymers were asshown in Table 4.

                  TABLE 3                                                         ______________________________________                                                         Amount of                                                                     comonomer fed                                                                             H.sub.2 /ethylene                                       Comonomer (kg/h)      molar ratio                                      ______________________________________                                        Example 4                                                                              1-Pentene   3.6         0.17                                         Comparative                                                                            1-Butene    3.7         0.16                                         Example 3                                                                     Comparative                                                                            1-Hexene    2.8         0.17                                         Example 4                                                                     ______________________________________                                    

                                      TABLE 4                                     __________________________________________________________________________                                           Content                                                        Impact                                                                             Tear      of                                                             strength                                                                           strength  Comonomer                                           MFR   Density                                                                            of film                                                                            MD/TD  Hh/                                                                              unit                                   Run   Comonomer                                                                            (g/10 min)                                                                          (g/cm.sup.3)                                                                       (kg/cm)                                                                            (kg/cm)                                                                            RS                                                                              H1 Wt % (mol %)                           __________________________________________________________________________    Example 3                                                                           1-Pentene                                                                            1.1   0.923                                                                              2500 60/145                                                                             42                                                                              4.3                                                                              8(3.4)                                 Example 4                                                                           1-Pentene                                                                            1.2   0.915                                                                              4900 65/155                                                                             75                                                                              3.3                                                                              12(5.2)                                Compara-                                                                            1-Butene                                                                             1.0   0.925                                                                               800 35/95                                                                              23                                                                              2.8                                                                              7(3.6)                                 tive                                                                          Example 3                                                                     Compara-                                                                            1-Hexene                                                                             1.1   0.923                                                                              2600 85/220                                                                             31                                                                              5.0                                                                              8(2.8)                                 tive                                                                          Example 4                                                                     __________________________________________________________________________

EXAMPLE 5

Using a 250-liter polymerizer, ethylene and 1-pentene, both suspended inhexane, were copolymerized continuously in the presence of thepre-polymerized catalyst and a mixture (1/1 molar ratio) oftriethylaluminum and diethylaluminum chloride.

The polymerization conditions employed and the results of polymerizationobtained were as shown in Table 5, and the results of evaluation of thefilms obtained therefrom were as shown in Table 6.

COMPARATIVE EXAMPLES 5 AND 6

The copolymerization of Example 5 was repeated but employing modifiedconditions as shown in Table 5 to obtain copolymers respectively shownin Table 6.

The results of evaluation of the films obtained from the copolymers wereas shown in Table 6.

                                      TABLE 5                                     __________________________________________________________________________               Polymeri-                                                                     zation     Amount of                                                                           Amount of    Resi-                                                                              Polymerization                                                                             MFR                           Pressure                                                                            Ti concn.                                                                          ethylene                                                                            comonomer                                                                           H.sub.2 /ethylene                                                                    dence                                                                              activity                                                                              Density                                                                            (g/10              Comonomer  (kg/cm.sup.2 G)                                                                     (mM/l)                                                                             fed (kg/h)                                                                          fed (kg/h)                                                                          molar ratio                                                                          time (hr)                                                                          (g-PE/mM-Ti)                                                                          (g/cm.sup.3)                                                                       min.)              __________________________________________________________________________    Ex. 5                                                                             1-Pentene                                                                            4.2   0.027                                                                              10    3.1   0.52   2.2  10,600  0.930                                                                              1.22               Comp.                                                                             1-Hexene                                                                             4.5   0.023                                                                               9    9     0.51   2.0   9,200  0.930                                                                              1.35               Ex. 5                                                                         Comp.                                                                             1-Butene                                                                             3.7   0.032                                                                              12    1.4   0.54   2.5  12,600  0.929                                                                              1.25               Ex. 6                                                                         __________________________________________________________________________

The polymerization temperature: 70° C., Al/Ti molar ratio at the time ofpolymerization: 10, and the slurry concentration at the time ofpolymerization: 250 g-polymer/l.

                                      TABLE 6                                     __________________________________________________________________________                                        Content                                                           Impact                                                                             Tear   of                                                                strength                                                                           strength                                                                             Comonomer                                              MFR   Density                                                                            of film                                                                            MD/TD  unit                                      Run   Comonomer                                                                            (g/10 min)                                                                          (g/cm.sup.3)                                                                       (kg/cm)                                                                            (kg/cm)                                                                            RS                                                                              Wt % (mol %)                              __________________________________________________________________________    Example 5                                                                           1-Pentene                                                                            1.22  0.930                                                                              1600 30/65                                                                              53                                                                              5(2.1)                                    Compara-                                                                            1-Hexenee                                                                            1.35  0.930                                                                              1600  85/100                                                                            19                                                                              2(1.0)                                    tive                                                                          Example 5                                                                     Compara-                                                                            1-Butene                                                                             1.25  0.929                                                                               600 25/60                                                                              24                                                                              6(3.1)                                    tive                                                                          Example 6                                                                     __________________________________________________________________________

EXAMPLE 6

To a polymerizer having a diameter of 40 cm φ and a capacity of 400 lshown in FIG. 3 were fed continuously through a pipe 1 thepre-polymerized catalyst prepared in Example 1 suspended in hexane andtriisobutylaluminum, at a rate of 0.5 mmol/hr in terms of Ti atom and arate of 25 mmol/hr, respectively, and simultaneously were fed through apipe 2 ethylene at a rate of 9.3 kg/hr and 1-pentene at a rate of 3.4kg/hr, and was fed through a pipe 3 hydrogen in such an amount that H₂/ethylene molar ratio in the polymerizer becomes 0.14.

The polymerization conditions employed were such that the pressure is 18kg/cm² G, the polymerization temperature is 80° C., the residence timesis 4 hours, and the linear velocity of the circulating gas in the vaporphase polymerizer is maintained at a rate of 45 cm/sec. The circulatinggas from a pipe 4 passed through a condenser B and circulated to thepolymerizer through a fan C.

The resulting copolymer was discharged through a pipe 5 out of thesystem at a rate of 4.5 kg/hr. The thus obtained copolymer had a densityof 0.921 g/cm³ and MFR of 2.2 g/10 min.

The copolymer was pelletized at a temperature of 200° C. by means of anextruder having a screw diameter of 45 mm φ.

The pellets obtained were formed by means of a commercially availableT-die film forming machine equipped with an extruder of 65 mm φ into afilm of 420 mm in width and 0.04 mm in thickness. At the time of filmforming, the resin temperature was 235° C., the film forming speed was20 m/min, and a draft ratio was 0.057.

MFR, impact strength, resistance to heat aging and weathering resistanceof the film obtained were evaluated. Results obtained were as shown inTable 8.

EXAMPLES 7-30

The same film forming operation as in Example 6 was repeated except butusing the pellets obtained respectively by pelletizing the copolymerobtained in Example 6 to which each of various stabilizers as shown inTable 7 has been added in an amount shown in Table 7. Results obtainedare shown in Table 8.

                                      TABLE 7                                     __________________________________________________________________________    Amount of stabilizer added (part by weight)                                   Example                                                                            A  B  C  D  E  F  G  H  I  J  K  L  M                                    __________________________________________________________________________    6    -- -- -- -- -- -- -- -- -- -- -- --                                      7    0.10                                                                     8    0.10                       0.10                                          9    -- 0.10                    0.10                                          10   0.10  0.10                 0.10                                          11   0.10     0.10              0.10                                          12   0.10        0.10           0.10                                          13   0.10                 0.10  0.10                                          14         0.10                                                               15         0.10                 0.10                                          16            0.10              0.10                                          17         0.10  0.10           0.10                                          18         0.10           0.10  0.10                                          19               0.10                                                         20               0.10           0.10                                          21                  0.10        0.10                                          22                     0.10     0.10                                          23               0.10     0.10  0.10                                          24                        0.10                                                25                        0.10  0.10                                          26                           0.10                                                                             0.10                                          27                              0.10                                          28                                 0.10                                       29                                    0.10                                    30                                       0.10                                 __________________________________________________________________________

                  TABLE 8                                                         ______________________________________                                                         Impact     Resistance                                                                             Weathering                               Ex-   MFR        strength   to heat aging                                                                          resistance                               ample Pellet  Film   (kg · cm/cm)                                                                  (day)    (%)                                    ______________________________________                                        6     1.6     1.2    2500      17      10                                     7     2.1     2.0    3000     200      35                                     8     2.1     2.0    3000     220      40                                     9     2.1     2.0    3100     350      40                                     10    2.2     2.1    3100     250      50                                     11    2.2     2.1    3100     260      45                                     12    2.1     2.0    3100     330      40                                     13    2.1     2.0    3000     290      90                                     14    2.0     1.9    3000      80      30                                     15    2.1     2.0    3000     100      35                                     16    2.1     2.0    3000     120      35                                     17    2.1     2.0    3000     150      30                                     18    2.1     2.0    3000     200      70                                     19    1.9     1.6    2900      50      20                                     20    1.9     1.7    2900      60      25                                     21    1.8     1.6    2900      70      25                                     22    1.9     1.7    2900      90      30                                     23    1.9     1.7    2900     150      60                                     24    1.9     1.6    2800     140      55                                     25    1.9     1.7    2900     160      60                                     26    1.9     1.7    2900     250      70                                     27    1.7     1.5    2800      30      25                                     28    1.7     1.5    2800      35      30                                     29    1.7     1.5    2800      30      25                                     30    1.7     1.5    2800      30      30                                     ______________________________________                                    

What is claimed is:
 1. An ethylene/pentene-1 copolymer which is obtainedby copolymerization of ethylene and pentene-1 and fulfills the followingrequisites (A) to (E):(A) a melt flow rate of the copolymer as measuredaccording to ASTM D 1238E is 0.01-100 g/10 min, (B) a density of thecopolymer as measured according to ASTM D 1505 is 0.87-0.96 g/cm³, (C)the copolymer contains constitution units derived from pentene-1 in anamount of 1-25% by weight, and (D) in the case that said copolymer issubjected to cast molding to prepare a film having a thickness of 40 μm,a ratio (RS) of impact strength of the film to tearing strength of thefilm in the take-off direction of the film satisfies the followingformula:

    RS≧-20 log MFR-1000d+968

wherein MFR represents a melt flow rate of said copolymer, and drepresents a density of said copolymer, and (E) in the case that saidcopolymer is melted at 200° C., then slowly cooled to 50° C. at acooling rate of 0.31° C./min and crystallized to prepare a sheet samplehaving a thickness of 0.5 mm, a DSC melt-peak pattern of the sampleobtained when the sample is heated from 10° to 200° C. at a heating rateof 10° C./min using DSC has two melt peaks, and a ratio (Hh/Hl) of aheight of the peak (Hh) on the higher temperature side to a height ofthe peak (Hl) on the lower temperature side and the density of saidcopolymer satisfy the following formula:

    60d-52.0<Hh/Hl<80d-69.0

wherein Hh represents a peak height on the higher temperature side, Hlrepresents a peak height on the lower temperature side, and d representsa density of said copolymer.
 2. An ethylene/pentene-1 copolymer obtainedby copolymerizing at least ethylene and pentene-1 in the presence of anolefin polymerization catalyst formed from[A] a solid titanium catalystcomponent containingmagnesium, titanium, halogen and an electron donoras its essential ingredients obtained by bringing (i) a liquid magnesiumcompound having no reducing ability and (ii) a liquid titanium compoundinto contact, as they are, with each other in the presence of (iii) anelectron donor having no active hydrogen, or by bringing said (i) andsaid (ii) into contact, as they are, with each other, followed bycontact with said (iii), and [B] an organic compound catalyst componentof a metal belonging to the Groups I to III of the periodic table; saidethylene/pentene-1 copolymer fulfilling the following requisites (A) to(E):(A) a melt flow rate of the copolymer as measured according to ASTMD 1238E is 0.01-100 g/10 min, (B) a density of the copolymer as measuredaccording to ASTM D 1505 is 0.87-0.96 g/cm³, (C) the copolymer containsconstitution units derived from pentene-1 in an amount of 1-25% byweight, and (D) in the case that said copolymer is subjected to castmolding to prepare a film having a thickness of 40 μm, a ratio (RS) ofimpact strength of the film to tearing strength of the film in thetake-off direction of the film satisfies the following formula:

    RS≧-20 log MFR-1000d+968

wherein MFR represents a melt flow rate of said copolymer, and drepresents a density of said copolymer and (E) in the case that saidcopolymer is melted at 200° C., then slowly cooled to 50° C. at acooling rate of 0.31° C./min and crystallized to prepare a sheet samplehaving a thickness of 0.5 mm, a DSC melt-peak pattern of the sampleobtained when the sample is heated from 10° to 200° C. at a heating rateof 10° C./min using DSC has two melt peaks, and a ratio (Hh/Hl) of aheight of the peak (Hh) on the higher temperature side to a height ofthe peak (Hl) on the lower temperature side and the density of saidcopolymer satisfy the following formula:

    60d-52.0<Hh/Hl<80d-69.0

wherein Hh represents a peak height on the higher temperature side, Hlrepresents a peak height on the lower temperature side, and d representsa density of said copolymer.
 3. An ethylene/pentene-1 copolymer obtainedby vapor phase copolymerization of ethylene and pentene-1 satisfying thefollowing requirements (A)-(E):(A) a melt flow rate of the copolymer asmeasured according to ASTM D 1238E is 0.01-100 g/10 min, (B) a densityof the copolymer as measured according to ASTM D 1505 is 0.88-0.95g/cm³, (C) the copolymer contains constitution units derived frompentene-1 in an amount of 2-25% by weight (D) in the case that saidcopolymer is subjected to cast molding to prepare a film having athickness of 40 μm, a ratio (RS) of impact strength of the film totearing strength of the film in the take-off direction of the filmsatisfies the following formula:

    RS≧-20 log MFR-1000d+968

wherein MFR represents a melt flow rate of said copolymer, and drepresents a density of said copolymer; and (E) in the case that saidcopolymer is melted at 200° C., then slowly cooled to 50° C. at acooling rate of 0.31° C./min and crystallized to prepare a sheet samplehaving a thickness of 0.5 mm, a DSC melt-peak pattern of the sampleobtained when the sample is heated from 10° to 200° C. at a heating rateof 10° C./min using DSC has two melt peaks, and a ratio (Hh/Hl) of aheight of the peak (Hh) on the higher temperature side to a height ofthe peak (Hl) on the lower temperature side and the density of saidcopolymer satisfy the following formula:

    60d-52.0<Hh/Hl<80d-69.0

wherein Hh represents a peak height on the higher temperature side, Hlrepresents a peak height on the lower temperature side, and d representsa density of said copolymer.
 4. An ethylene/pentene-1 copolymer obtainedby vapor phase copolymerization of ethylene and pentene-1 in thepresence of an olefin polymerization catalyst formed from a solidtitanium catalyst component [A] for olefin polymerization obtained byreaction of a hydrocarbon-insoluble solid magnesium aluminum compositeselected from (A₁) or (A₂) mentioned below and tetravalent titaniumcompound and containing at least titanium atoms in a low valent state inthe proportion of more than 10% and having OR group in an amount of from1 to 15 in terms of OR/Mg (weight ratio) and an organoaluminum compoundcatalyst component [B], said (A₁) representing a solidmagnesium·aluminum composite having R¹ O group and R² group (R¹ and R²is each a hydrocarbon residue) obtained from a liquid magnesium compoundformed from a mixture containing a magnesium compound and an electrondonor or a liquid magnesium compound formed from a solution of amagnesium compound in hydrocarbon solvent, and said (A₂) representing asolid magnesium, aluminum composite containing R¹ O group and R³ group(R³ is a hydrocarbon residue) obtained by reaction of a solid magnesiumcompound (B) containing R¹ O group or R¹ OH group obtained from a liquidmagnesium compound formed from a mixture containing a magnesium compoundand an electron donor or a liquid magnesium compound formed from asolution of a magnesium compound in hydrocarbon solvent or theabove-mentioned (A₁) with an organometallic compound (C) of a metalbelonging to the group I through III of the periodic table;saidethylene/pentene-1 copolymer satisfying the following requirements(A)-(E):(A) a melt flow rate of the copolymer as measured according toASTM D 1238E is 0.01-100 g/10 min, (B) a density of the copolymer asmeasured according to ASTM D 1505 is 0.88-0.95 g/cm³, (C) the copolymercontains constitution units derived from pentene-1 in an amount of 2-25%by weight (D) in the case that said copolymer is subjected to castmolding to prepare a film having a thickness of 40 μm, a ratio (RS) ofimpact strength of the film to tearing strength of the film in thetake-off direction of the film satisfies the following formula:

    RS≧-20 log MFR-1000d+968

wherein MFR represents a melt flow rate of said copolymer, and drepresents a density of said copolymer; and (E) in the case that saidcopolymer is melted at 200° C., then slowly cooled to 50° C. at acooling rate of 0.31° C./min and crystallized to prepare a sheet samplehaving a thickness of 0.5 mm, a DSC melt-peak pattern of the sampleobtained when the sample is heated from 10° to 200° C. at a heating rateof 10° C./min using DSC has two melt peaks, and a ratio (Hh/Hl) of aheight of the peak (Hh) on the higher temperature side to a height ofthe peak (Hl) on the lower temperature side and the density of saidcopolymer satisfy the following formula:

    60d-52.0<Hh/Hl<80d-69.0

wherein Hh represents a peak height on the higher temperature side, Hlrepresents a peak height on the lower temperature side, and d representsa density of said copolymer.
 5. An ethylene/pentene-1 copolymer obtainedby suspension copolymerization of ethylene and pentene-1 satisfying thefollowing requirements (A)-(E):(A) a melt flow rate of the copolymer asmeasured according to ASTM D 1238E is 0.01-100 g/10 min, (B) a densityof the copolymer as measured according to ASTM D 1505 is 0.90-0.96g/cm³, (C) the copolymer contains constitution units derived frompentene-1 in an amount of 2-15% by weight (D) in the case that saidcopolymer is subjected to cast molding to prepare a film having athickness of 40 μm, a ratio (RS) of impact strength of the film totearing strength of the film in the take-off direction of the filmsatisfies the following formula:

    RS≧-20 log MFR-1000d+968

wherein MFR represents a melt flow rate of said copolymer, and drepresents a density of said copolymer; and (E) in the case that saidcopolymer is melted at 200° C., then slowly cooled to 50° C. at acooling rate of 0.31° C./min and crystallized to prepare a sheet samplehaving a thickness of 0.5 mm, a DSC melt-peak pattern of the sampleobtained when the sample is heated from 10° to 200° C. at a heating rateof 10° C./min using DSC has two melt peaks, and a ratio (Hh/Hl) of aheight of the peak (Hh) on the higher temperature side to a height ofthe peak (Hl) on the lower temperature side and the density of saidcopolymer satisfy the following formula:

    60d-52.0<Hh/Hl<80d-69.0

wherein Hh represents a peak height on the higher temperature side, Hlrepresents a peak height on the lower temperature side, and d representsa density of said copolymer.
 6. An ethylene/pentene-1 copolymer obtainedby suspension copolymerization of ethylene and pentene-1 in the presenceof an olefin polymerization catalyst formed from a solid titaniumcatalyst component [A] for olefin polymerization obtained by reaction ofa hydrocarbon-insoluble solid magnesium aluminum composite selected from(A₁) or (A₂) mentioned below and a tetravalent titanium compound andcontaining at least titanium atoms in a low valent state in theproportion of more than 10% and having OR group in an amount of from 1to 15 in terms of OR/Mg (weight ratio) and an organoaluminum compoundcatalyst component [B], said (A₁) representing a solidmagnesium·aluminum composite having R¹ O group and R² group (R¹ and R²is each a hydrocarbon residue) obtained from a liquid magnesium compoundformed from a mixture containing a magnesium compound and an electrondonor or a liquid magnesium compound formed from a solution of amagnesium compound in hydrocarbon solvent, and said (A₂) representing asolid magnesium, aluminum composite containing R¹ O group and R³ group(R³ is a hydrocarbon residue) obtained by reaction of a solid magnesiumcompound (B) containing R¹ O group or R¹ OH group obtained from a liquidmagnesium compound formed from a mixture containing a magnesium compoundand an electron donor or a liquid magnesium compound formed from asolution of a magnesium compound in hydrocarbon solvent or theabove-mentioned (A₁) with an organometallic compound (C) of a metalbelonging to the group I through III of the periodic table;wherein thepolymerization is carried out at a state where more than 30% by weightof the resulting copolymer is not eluted and a polymerizationtemperature of 0°-120° C. to prepare, and said ethylene/pentene-1copolymer satisfying the following requirements (A)-(E):(A) a melt flowrate of the copolymer as measured according to ASTM D 1238E is 0.01-100g/10 min, (B) a density of the copolymer as measured according to ASTM D1505 is 0.90-0.96 g/cm³, (C) the copolymer contains constitution unitsderived from pentene-1 in an amount of 2-15% by weight (D) in the casethat said copolymer is subjected to cast molding to prepare a filmhaving a thickness of 40 μm, a ratio (RS) of impact strength of the filmto tearing strength of the film in the take-off direction of the filmsatisfies the following formula:

    RS≧-20log MFR-1000d+968

wherein MFR represents a melt flow rate of said copolymer, and drepresents a density of said copolymer; and (E) in the case that saidcopolymer is melted at 200° C., then slowly cooled to 50° C. at acooling rate of 0.31° C./min and crystallized to prepare a sheet samplehaving a thickness of 0.5 mm, a DSC melt-peak pattern of the sampleobtained when the sample is heated from 10° to 200° C. at a heating rateof 10° C./min using DSC has two melt peaks, and a ratio (Hh/Hl) of aheight of the peak (Hh) on the higher temperature side to a height ofthe peak (Hl) on the lower temperature side and the density of saidcopolymer satisfy the following formula:

    60d-52.0<Hh/Hl<80d-69.0

wherein Hh represents a peak height on the higher temperature side, Hlrepresents a peak height on the lower temperature side, and d representsa density of said copolymer.
 7. A film formed from theethylene/pentene-1 copolymer as claimed in any one of claims 1 to
 6. 8.An ethylene/pentene-1 copolymer composition comprising anethylene/pentene-1 copolymer (I) and at least one compound (II) selectedfrom the group consisting of a phenolic stabilizer (a), an organicphosphite stabilizer (b), a thioether stabilizer (c), a hindered aminestabilizer (d) and a metal salt of a higher aliphatic acid (e);saidethylene/pentene-1 copolymer (I) being obtained by copolymerization ofethylene and pentene-1 and fulfilling the following requisites (A) to(E): (A) a melt flow rate of the copolymer as measured according to ASTMD 1238E is 0.01-100 g/10 min, (B) a density of the copolymer as measuredaccording to ASTM D 1505 is 0.87-0.96 g/cm³, (C) the copolymer containsconstitution units derived from pentene-1 in an amount of 1-25% byweight, (D) in the case that said copolymer is subjected to cast moldingto prepare a film having a thickness of 40 μm, a ratio (RS) of impactstrength of the film to tearing strength of the film in the take-offdirection of the film satisfies the following formula:

    RS≧-20 log MFR-1000d+968

wherein MFR represents a melt flow rate of said copolymer, and drepresents a density of said copolymer, and (E) in the case that saidcopolymer is melted at 200° C., then slowly cooled to 50° C. at acooling rate of 0.31° C./min and crystallized to prepare a sheet samplehaving a thickness of 0.5 mm, a DSC melt-peak pattern of the sampleobtained when the same is heated from 10° to 200° C. at a heating rateof 10° C./min using DSC has two melt peaks, and a ratio (Hh/Hl) of aheight of the peak (Hh) on the higher temperature side to a height ofthe peak (Hl) on the lower temperature side and the density of saidcopolymer satisfy the following formula:

    60d-52.0<Hh/Hl<80d-69.0

wherein Hh represents a peak height on the higher temperature side, Hlrepresents a peak height on the lower temperature side, and d representsa density of said copolymer.
 9. The ethylene/pentene-1 copolymercomposition as claimed in claim 8, wherein said composition comprises100 parts by weight of the ethylene/pentene-1 copolymer (I) and 0.005-5parts by weight of the phenolic stabilizer (a).
 10. Theethylene/pentene-1 copolymer composition as claimed in claim 8, whereinsaid composition comprises 100 parts by weight of the ethylene/pentene-1copolymer (I), 0.005-5 parts by weight of the phenolic stabilizer (a)and 0.005-5 parts by weight of at least one compound selected from thegroup consisting of the organic phosphite stabilizer (b), the thioetherstabilizer (c), the hindered amine stabilizer (d) and the metal salt ofa higher aliphatic acid (e).
 11. The ethylene/pentene-1 copolymercomposition as claimed in claim 8, wherein said composition comprises100 parts by weight of the ethylene/pentene-1 copolymer (I) and 0.005-5parts by weight of the organic phosphite stabilizer (b).
 12. Theethylene/pentene-1 copolymer composition as claimed in claim 8, whereinsaid composition comprises 100 parts by weight of the ethylene/pentene-1copolymer (I), 0.005-5 parts by weight of the organic phosphitestabilizer (b) and 0.005-5 parts by weight of at least one compoundselected from the group consisting of the thioether stabilizer (c), thehindered amine stabilizer (d) and the metal salt of a higher aliphaticacid (e).
 13. The ethylene/pentene-1 copolymer composition as claimed inclaim 8, wherein said composition comprises 100 parts by weight of theethylene/pentene-1 copolymer (I) and 0.005-5 parts by weight of thethioether stabilizer (c).
 14. The ethylene/pentene-1 copolymercomposition as claimed in claim 8, wherein said composition comprises100 parts by weight of the ethylene/pentene-1 copolymer (I), 0.005-5parts by weight of the thioether stabilizer (c) and 0.005-5 parts byweight of at least one compound selected from the group consisting ofthe hindered amine stabilizer (d) and the metal salt of a higheraliphatic acid (e).
 15. The ethylene/pentene-1 copolymer composition asclaimed in claim 8, wherein said composition comprises 100 parts byweight of the ethylene/pentene-1 copolymer (I) and 0.005-5 parts byweight of the hindered amine stabilizer (d).
 16. The ethylene/pentene-1copolymer composition as claimed in claim 8, wherein said compositioncomprises 100 parts by weight of the ethylene/pentene-1 copolymer (I),0.005-5 parts by weight of the hindered amine type stabilizer (d) and0.005-5 parts by weight of the metal salt of a higher aliphatic acid(e).
 17. The ethylene/pentene-1 copolymer composition as claimed inclaim 8, wherein said composition comprises 100 parts by weight of theethylene/pentene-1 copolymer (I) and 0.005-5 parts by weight of themetal salt of a higher aliphatic acid (e).
 18. An ethylene/pentene-1copolymer composition comprising an ethylene/pentene-1 copolymer (Ia)and at least one compound (II) selected from the group consisting of aphenolic stabilizer (a), an organic phosphite stabilizer (b), athioether stabilizer (c), a hindered amine stabilizer (d) and a metalsalt of a higher aliphatic acid (e);said ethylene/pentene-1 copolymer(Ia) being obtained by copolymerizing ethylene and pentene-1 in thepresence of an olefin polymerization catalyst formed from(a) a solidtitanium catalyst component containing magnesium, titanium, halogen andan electron donor as its essential ingredients obtained by bringing (i)a liquid magnesium compound having no reducing ability and (ii) a liquidtitanium compound into contact, as they are, with each other in thepresence of (iii) an electron donor having no active hydrogen, or bybringing said (i) and said (ii) into contact, as they are, with eachother, followed by contact with said (iii), and (b) an organic compoundcatalyst component of a metal belonging to the Groups I to III of theperiodic table; said ethylene/pentene-1 copolymer fulfilling thefollowing requisites (A) to (E):(A) a melt flow rate of the copolymer asmeasured according to ASTM D 1238E is 0.01-100 g/10 min, (B) a densityof the copolymer as measured according to ASTM D 1505 is 0.97-0.96g/cm³, (C) the copolymer contains constitution units derived frompentene-1 in an amount of 1-25% by weight, (D) in the case that saidcopolymer is subjected to cast molding to prepare a film having athickness of 40 μm, a ratio (RS) of impact strength of the film in thetake-off direction of the film satisfies the following formula:

    RS≧-20 log MFR-1000d+968

wherein MFR represents a melt flow rate of said copolymer, and drepresents a density of said copolymer, and (E) in the case that saidcopolymer is melted at 200° C., then slowly cooled to 50° C. at acooling rate of 0.31° C./min and crystallized to prepare a sheet samplehaving a thickness of 0.5 mm, a DSC melt-peak pattern of the sampleobtained when the sample is heated from 10° to 200° C., at a heatingrate of 10° C./min using DSC has two melt peaks, and a ratio (Hh/Hl) ofa height of the peak (Hh) on the higher temperature side to a height ofthe peak (Hl) on the lower temperature side and the density of saidcopolymer satisfy the following formula:

    60d-52.0<Hh/Hl<80d-69.0

wherein Hh represents a peak height on the higher temperature side, Hlrepresents a peak temperature on the lower temperature side, and drepresents a density of said copolymer.
 19. The ethylene/pentene-1copolymer composition as claimed in claim 18, wherein said compositioncomprises 100 parts by weight of the ethylene/pentene-1 copolymer (Ia)and 0.005-5 parts by weight of the phenolic stabilizer (a).
 20. Theethylene/pentene-1 copolymer composition as claimed in claim 18, whereinsaid composition comprises 100 parts by weight of the ethylene/pentene-1copolymer (Ia), 0.005-5 parts by weight of the phenolic stabilizer (a)and 0.005-5 parts by weight of at least one compound selected from thegroup consisting of the organic phosphite stabilizer (b), the thioetherstabilizer (c), the hindered amine stabilizer (d) and the metal salt ofa higher aliphatic acid (e).
 21. The ethylene/pentene-1 copolymercomposition as claimed in claim 18, wherein said composition comprises100 parts by weight of the ethylene/pentene-1 copolymer (Ia) and 0.005-5parts by weight of the organic phosphite stabilizer (b).
 22. Theethylene/pentene-1 copolymer composition as claimed in claim 18, whereinsaid composition comprises 100 parts by weight of the ethylene/pentene-1copolymer (Ia), 0.005-5 parts by weight of the organic phosphitestabilizer (b) and 0.005 to 5 parts by weight of at least one compoundselected from the group consisting of the thioether stabilizer (c), thehindered amine stabilizer (d) and the metal salt of a higher aliphaticacid (e).
 23. The ethylene/pentene-1 copolymer composition as claimed inclaim 18, wherein said composition comprises 100 parts by weight of theethylene/pentene-1 copolymer (Ia) and 0.005-5 parts by weight of thethioether stabilizer (c).
 24. The ethylene/pentene-1 copolymercomposition as claimed in claim 18, wherein said composition comprises100 parts by weight of the ethylene/pentene-1 copolymer (Ia), 0.005-5parts by weight of the thioether stabilizer (c) and 0.005-5 parts byweight of at least one compound selected from the group consisting ofthe hindered amine stabilizer (d) and the metal salt of a higheraliphatic acid (e).
 25. The ethylene/pentene-1 copolymer composition asclaimed in claim 18, wherein said composition comprises 100 parts byweight of the ethylene/pentene-1 copolymer (Ia) and 0.005-5 parts byweight of the hindered amine stabilizer (d).
 26. The ethylene/pentene-1copolymer composition as claimed in claim 18, wherein said compositioncomprises 100 parts by weight of the ethylene/pentene-1 copolymer (Ia),0.005-5 parts by weight of the hindered amine stabilizer (d) and 0.005-5parts by weight of the metal salt of a higher aliphatic acid (e). 27.The ethylene/pentene-1 copolymer composition as claimed in claim 18,wherein said composition comprises 100 parts by weight of theethylene/pentene-1 copolymer (Ia) and 0.005-5 parts by weight of themetal salt of a higher aliphatic acid (e).
 28. An ethylene/pentene-1copolymer composition comprising an ethylene/pentene-1 copolymer (Ib)and at least one compound (II) selected from the group consisting of aphenolic stabilizer (a), an organic phosphite stabilizer (b), athioether stabilizer (c), a hindered amine stabilizer (d) and a metalsalt of a higher aliphatic acid (e);said ethylene/pentene-1 copolymer(Ib) being obtained by vapor phase copolymerization of ethylene andpentene-1 in the presence of an olefin polymerization catalyst formedfrom a solid titanium catalyst component [A ]for olefin polymerizationobtained by reaction of a hydrocarbon-insoluble solid magnesium aluminumcomposite selected from (A₁) or (A₂) mentioned below and a tetravalenttitanium compound and containing at least titanium atoms in a low valentstate in the proportion of more than 10% and having OR group in anamount of from 1 to 15 in terms of OR/Mg (weight ratio) and anorganoaluminum compound catalyst component, said (A₁) representing asolid magnesium.aluminum composite having R¹ O group and R² group (R¹and R² is each a hydrocarbon residue) obtained from a liquid magnesiumcompound formed from a mixture containing a magnesium compound and anelectron donor or a liquid magnesium compound formed from a solution ofa magnesium compound in hydrocarbon solvent, and said (A₂) representinga solid magnesium, aluminum composite containing R¹ O group and R³ group(R³ is a hydrocarbon residue) obtained by reaction of a solid magnesiumcompound (B) containing R¹ O group or R¹ OH group obtained from a liquidmagnesium compound formed from a mixture containing a magnesium compoundand an electron donor or a liquid magnesium compound formed from asolution of a magnesium compound in hydrocarbon solvent or theabove-mentioned (A₁) with an organometallic compound (C) of a metalbelonging to the group I through III of the periodic table; saidethylene/pentene-1 copolymer satisfying the following requirements(A)-(E):(A) a melt flow rate of the copolymer as measured according toASTM D 1238E is 0.01-100 g/10 min, (B) a density of the copolymer asmeasured according to ASTM D 1505 is 0.88-0.95 g/cm³, (C) the copolymercontains constitution units derived from pentene-1 in an amount of 2-25%by weight (D) in the case that said copolymer is subjected to castmolding to prepare a film having a thickness of 40 μm, a ratio (RS) ofimpact strength of the film to tearing strength of the film in thetake-off direction of the film satisfies the following formula:

    RS≧-20 log MFR-1000d+968

wherein MFR represents a melt flow rate of said copolymer, and drepresents a density of said copolymer; and (E) in the case that saidcopolymer is melted at 200° C., then slowly cooled to 50° C. at acooling rate of 0.31° C./min and crystallized to prepare a sheet samplehaving a thickness of 0.5 mm, a DSC melt-peak pattern of the sampleobtained when the sample is heated from 10° to 200° C. at a heating rateof 10° C./min using DSC has two melt peaks, and a ratio (Hh/Hl) of aheight of the peak (Hh) on the higher temperature side to a height ofthe peak (Hl) on the lower temperature side and the density of saidcopolymer satisfy the following formula:

    60d-52.0<Hh/Hl<80d-69.0

wherein Hh represents a peak height on the higher temperature side, Hlrepresents a peak height on the lower temperature side, and d representsa density of said copolymer.
 29. The ethylene/pentene-1 copolymercomposition as claimed in claim 28, wherein said composition comprises100 parts by weight of the ethylene/pentene-1 copolymer (Ib) and 0.005-5parts by weight of the phenolic stabilizer (a).
 30. Theethylene/pentene-1 copolymer composition as claimed in claim 28, whereinsaid composition comprises 100 parts by weight of the ethylene/pentene-1copolymer (Ib), 0.005-5 parts by weight of the phenolic stabilizer (a)and 0.005-5 parts by weight of at least one compound selected from thegroup consisting of the organic phosphite stabilizer (b), the thioetherstabilizer (c), the hindered amine stabilizer (d) and the metal salt ofa higher aliphatic acid (e).
 31. The ethylene/pentene-1 copolymercomposition as claimed in claim 28, wherein said composition comprises100 parts by weight of the ethylene/pentene-1 copolymer (Ib) and 0.005-5parts by weight of the organic phosphite stabilizer (b).
 32. Theethylene/pentene-1 copolymer composition as claimed in claim 28, whereinsaid composition comprises 100 parts by weight of the ethylene/pentene-1copolymer (Ib), 0.005-5 parts by weight of the organic phosphitestabilizer (b) and 0.005 to 5 parts by weight of at least one compoundselected from the group consisting of the thioether stabilizer (c), thehindered amine stabilizer (d) and the metal salt of a higher aliphaticacid (e).
 33. The ethylene/pentene-1 copolymer composition as claimed inclaim 28, wherein said composition comprises 100 parts by weight of theethylene/pentene-1 copolymer (Ib) and 0.005-5 parts by weight of thethioether stabilizer (c).
 34. The ethylene/pentene-1 copolymercomposition as claimed in claim 28, wherein said composition comprises100 parts by weight of the ethylene/pentene-1 copolymer (Ib), 0.005-5parts by weight of the thioether stabilizer (c) and 0.005-5 parts byweight of at least one compound selected from the group consisting ofthe hindered amine stabilizer (d) and the metal salt of a higheraliphatic acid (e).
 35. The ethylene/pentene-1 copolymer composition asclaimed in claim 28, wherein said composition comprises 100 parts byweight of the ethylene/pentene-1 copolymer (Ib) and 0.005-5 parts byweight of the hindered amine stabilizer (d).
 36. The ethylene/pentene-1copolymer composition as claimed in claim 28, wherein said compositioncomprises 100 parts by weight of the ethylene/pentene-1 copolymer (Ib),0.005-5 parts by weight of the hindered amine stabilizer (d) and 0.005-5parts by weight of the metal salt of a higher aliphatic acid (e). 37.The ethylene/pentene-1 copolymer composition as claimed in claim 28,wherein said composition comprises 100 parts by weight of theethylene/pentene-1 copolymer (Ib) and 0.005-5 parts by weight of themetal salt of a higher aliphatic acid (e).
 38. An ethylene/pentene-1copolymer composition comprising an ethylene/pentene-1 copolymer (Ic)and at least one compound (II) selected from the group consisting of aphenolic stabilizer (a), an organic phosphite stabilizer (b), athioether stabilizer (c), a hindered amine stabilizer (d) and a metalsalt of a higher aliphatic acid (e);said ethylene/pentene-1 copolymer(Ic) being obtained by suspension copolymerization of ethylene andpentene-1 in the presence of an olefin polymerization catalyst formedfrom a solid titanium catalyst component [A] for olefin polymerizationobtained by reaction of a hydrocarbon-insoluble solid magnesium aluminumcomposite selected from (A₁) or (A₂) mentioned below and a tetravalenttitanium compound and containing at least titanium atoms in a low valentstate in the proportion of more than 10% and having OR group in anamount of from 1 to 15 in terms of OR/Mg (weight ratio) and anorganoaluminum compound catalyst component, said (A₁) representing asolid magnesium.aluminum composite having R¹ O group and R² group (R¹and R² is each a hydrocarbon residue) obtained from a liquid magnesiumcompound formed from a mixture containing a magnesium compound and anelectron donor or a liquid magnesium compound formed from a solution ofa magnesium compound in hydrocarbon solvent, and said (A₂) representinga solid magnesium, aluminum composite containing R¹ O group and R³ group(R³ is a hydrocarbon residue) obtained by reaction of a solid magnesiumcompound (B) containing R¹ O group or R¹ OH group obtained from a liquidmagnesium compound formed from a mixture containing a magnesium compoundand an electron donor or a liquid magnesium compound formed from asolution of a magnesium compound in hydrocarbon solvent or theabove-mentioned (A₁) with an organometallic compound (C) of a metalbelonging to the group I through III of the periodic table; wherein thepolymerization is carried out at a state where more than 30% by weightof the resulting copolymer is not eluted and a polymerizationtemperature of 0°-120° C. to prepare, and said ethylene/pentene-1copolymer satisfying the following requirements (A)-(E):(A) a melt flowrate of the copolymer as measured according to ASTM D 1238E is 0.01-100g/10 min, (B) a density of the copolymer as measured according to ASTM D1505 is 0.90-0.96 g/cm³, (C) the copolymer contains constitution unitsderived from pentene-1 in an amount of 2-15% by weight (D) in the casethat said copolymer is subjected to cast molding to prepare a filmhaving a thickness of 40 μm, a ratio (RS) of impact strength of the filmto tearing strength of the film in the take-off direction of the filmsatisfies the following formula:

    RS≧-20 log MFR-1000d+968

wherein MFR represents a melt flow rate of said copolymer, and drepresents a density of said copolymer; and (E) in the case that saidcopolymer is melted at 200° C., then slowly cooled to 50° C. at acooling rate of 0.31° C./min and crystallized to prepare a sheet samplehaving a thickness of 0.5 mm, a DSC melt-peak pattern of the sampleobtained when the sample is heated from 10° to 200° C. at a heating rateof 10° C./min using DSC has two melt peaks, and a ratio (Hh/Hl) of aheight of the peak (Hh) on the higher temperature side to a height ofthe peak (Hl) on the lower temperature side and the density of saidcopolymer satisfy the following formula:

    60d-52.0<Hh/Hl<80d-69.0

wherein Hh represents a peak height on the higher temperature side, Hlrepresents a peak height on the lower temperature side, and d representsa density of said copolymer.
 39. The ethylene/pentene-1 copolymercomposition as claimed in claim 38, wherein said composition comprises100 parts by weight of the ethylene/pentene-1 copolymer (Ic) and 0.005-5parts by weight of the phenolic stabilizer (a).
 40. Theethylene/pentene-1 copolymer composition as claimed in claim 38, whereinsaid composition comprises 100 parts by weight of the ethylene/pentene-1copolymer (Ic), 0.005-5 parts by weight of the phenolic stabilizer (a)and 0.005-5 parts by weight of at least one compound selected from thegroup consisting of the organic phosphite stabilizer (b), the thioetherstabilizer (c), the hindered amine stabilizer (d) and the metal salt ofa higher aliphatic acid (e).
 41. The ethylene/pentene-1 copolymercomposition as claimed in claim 38, wherein said composition comprises100 parts by weight of the ethylene/pentene-1 copolymer (Ic) and 0.005-5parts by weight of the organic phosphite stabilizer (b).
 42. Theethylene/pentene-1 copolymer composition as claimed in claim 38, whereinsaid composition comprises 100 parts by weight of the ethylene/pentene-1copolymer (Ic), 0.005-5 parts by weight of the organic phosphitestabilizer (b) and 0.005 to 5 parts by weight of at least one compoundselected from the group consisting of the thioether stabilizer (c), thehindered amine stabilizer (d) and the metal salt of a higher aliphaticacid (e).
 43. The ethylene/pentene-1 copolymer composition as claimed inclaim 38, wherein said composition comprises 100 parts by weight of theethylene/pentene-1 copolymer (Ic) and 0.005-5 parts by weight of thethioether stabilizer (c).
 44. The ethylene/pentene-1 copolymercomposition as claimed in claim 38, wherein said composition comprises100 parts by weight of the ethylene/pentene-1 copolymer (Ic), 0.005-5parts by weight of the thioether stabilizer (c) and 0.005-5 parts byweight of at least one compound selected from the group consisting ofthe hindered amine stabilizer (d) and the metal salt of a higheraliphatic acid (e).
 45. The ethylene/pentene-1 copolymer composition asclaimed in claim 38, wherein said composition comprises 100 parts byweight of the ethylene/pentene-1 copolymer (Ic) and 0.005-5 parts byweight of the hindered amine stabilizer (d).
 46. The ethylene/pentene-1copolymer composition as claimed in claim 38, wherein said compositioncomprises 100 parts by weight of the ethylene/pentene-1 copolymer (Ic),0.005-5 parts by weight of the hindered amine stabilizer (d) and 0.005-5parts by weight of the metal salt of a higher aliphatic acid (e). 47.The ethylene/pentene-1 copolymer composition as claimed in claim 38,wherein said composition comprises 100 parts by weight of theethylene/pentene-1 copolymer (Ic) and 0.005-5 parts by weight of themetal salt of a higher aliphatic acid (e).